 Hi, and welcome to the session. I am Shashi. Let us do one question. Question is, matrices A and B will be inverse of each other only if A part AB is equal to BA, B part AB is equal to BA is equal to 0, C part AB is equal to 0, BA is equal to I, where I is the identity matrix, D part AB is equal to BA is equal to I, where I is the identity matrix. We have to choose the correct answer from A, B, C and D. Let us now start with the solution. We know by the definition of invertible matrices if A is a square matrix of order M, other square matrix of same order M such that AB is equal to BA is equal to I, where I is the identity matrix. Then B is called inverse of A that is B is equal to A inverse and A is called inverse of B that is A is equal to B inverse. So, A and B will be inverse of each other only if AB is equal to BA is equal to I. So, our correct answer is D. So, required answer is D. This completes the session. Hope you understood the session. Take care and goodbye.