 Hello and welcome to the session. Let's work out the following question. It says choose the correct option, justify your choice. So this is a multiple choice question and we have to choose the correct option. The given expression is 1 plus tan square a upon 1 plus cot square a. Now we know that 1 plus tan square a is secant square a and 1 plus cot square a is cosecant square a. Now secant square a can be written as 1 upon cos square a and cosecant square a can be written as 1 upon sin square a. So this is equal to 1 upon cos square a into sin square a upon 1. So this is equal to sin square a upon cos square a which is equal to tan square a. So the given expression is equal to tan square a so the correct option is option d. So this completes the question and the session. Bye for now. Take care. Have a good day.