 Hello and welcome to the session. Let us understand the following question which says, to the correct answer, the rate of change of the area of a circle with respect to its radius r, as r is equal to 6 centimeter is A, 10 pi, V, 12 pi, C, 8 pi, D, 11 pi. Now let's proceed on to the solution. Here we have to find the rate of change of the area of a circle with respect to its radius, that is we have to find dA by dr. We know area of a circle is given by A is equal to pi r square. Now differentiating it with respect to r we get dA by dr is equal to 2 pi r. Now we have to find rate of change of area of the circle with respect to radius when r is equal to 6 centimeter. Therefore dA by dr at r is equal to 6 is equal to 2 multiplied by pi multiplied by 6, which is equal to 12 pi. Hence the correct option is B, which is the required answer. I hope you understood this question. Bye and have a nice day.