 that pertains to the consumer choices, how the consumption decision is made by a consumer. When we say that the consumer is going to decide something about the consumption, then there are certain prerequisites. Number one, consumer must have the information. Number two, consumer is having the power to decide. Number three, the consumer is able to express and then number four, the consumer is having the ability to compare the available bundles of the consumption pertaining to various information that he is having in his hand. So, if the consumer will having all these available information, he will be able to express the preferences and he has certain preferences and that is, he can decide related to the consumption and keeping in view his consumption decision, now he will be able to make purchasing decision. So, in the consumption decision, when we say the consumer is reaching a particular point of equilibrium, these point of equilibrium, they are of two types. Number one, we can say that there is interior type of solution or we can say the consumer is having exterior or the corner solution. So, the general level of the discussion or the theory that we are having in our mostly microeconomics topics, they are pertaining to the interior solution and interior solution is meant for all those decisions that are related to the trade-offs. But for corner solution, we will cover in any coming module, the consumer is not having the trade-off decision. Now, coming to the interior solution, we see that the consumer is always having or the facing one question, that how he has to maximize his utility to his satisfaction or if we say that he is satisfied with the commodity, we maximize it this way. Or for maximization of this solution, If we look at it, he is having one income and he is having a bundle of commodities whose prices are available and for that he has to decide how much he takes the quantity of those commodities. Now if we look at it, there are two things that we assume first. We say that the consumer who is using commodities, for that the marginal utility of each good is positive. And that positive marginal utility is because the bundles of the higher indifference curve will always prefer the lower level. And the consumer will always spend his income in complete form. If he does not fully utilize his income on some part, then he cannot come on a complete trade-off. So for the maximization of the utility, we see that on one side, the amount of the income that he is taking with him, the amount of income he has in his subject will always be utilized and he will go to this point that he will spend all of it. And the consumer will always select that bundle which is on the budget line. It means the consumer may have various indifference curves and the various available choices, but he will be on the best point when his budget and the maximization of the utility curve coincide. So in this frame, we can say that on one side, slope of the indifference curve we should have and on the other side, we should have the slope of the budget line. So when the slopes of these two lines equate to each other, then we can say that it comes to that the rate of change between the two commodities, it remains constant and it gives that much constant that it is equal to the rate of change in the money matters. So when the slope of these two, they become equal. When we explain this fact graphically, we can say the consumer is having one indifference curve here, consumer is having one this indifference curve, consumer is having this indifference curve or likewise there can be many here. But now the consumer will purchase one thing. The consumption decision is the choice decision. When the consumer will have certain amount to purchase in his pocket. So as per the given budget or consumer, looking at their purchasing parity, looking at their affordability, which draws their budget line, now he will see where his slope is equating with both of them. So there is one point when the indifference curve is with this budget line and at the same time, its budget line is touching a higher level of indifference curve. So now the consumer is having a dilemma that either he should purchase this bundle or he should purchase this bundle. So because the two bundles, they are affordable to the consumer, so consumer will definitely prefer that bundle that will have more and more of the both commodities to this. So the tangency solution is the main decision point that will make the consumer able to purchase his optimal bundle and that optimal bundle will give him the highest attainable satisfaction and that will be the highest attainable indifference curve to that consumer. Now if due to any condition or any blessing, the consumer's income can change from this to any other higher point like this. So at this point we see that the consumer is having this indifference curve coincidence here or he is having any other indifference curve that is like, then again the same decision he will be facing and now he will prefer this point that will be on certain higher level of the indifference curve as compared to the previous point. So keeping in view this, we are coming to a point that the consumer if shifting from this point to this point on the same indifference curve, it means he is switching from one point to other so he is having certain trade-off and this trade-off makes him possible to attain a point which can be the highest level for the consumer. So that trade-off is basically the rate of change or that is the marginal rate of substitution along that indifference curve and that marginal rate of indifference curve is particularly that is the rate at which consumer is willing to exchange for an extra unit of product for which he is going to sacrifice. Now if we look at an indifference curve along its negative slope and its rate of change or if we look at the rate of exchange between good on x-axis and between the commodity on the y-axis, this is possible for a consumer to attain his highest level because it will give him his slope and this slope will help out to having the equality with the budget line. So consumption choices may slope of indifference curve is the main point as the same point other is the slope of the budget line that makes the consumer possible to attain a point where we can say that the consumer is having the maximum level of the consumption and at this point we can say the rate of change of utilities is equal to that the slope of the budget line. Thank you.