# Solve this following

Question:

If $\mathrm{A}$ is an $3 \times 3$ non-singular matrix such that $\mathrm{AA}^{\prime}=\mathrm{A}^{\prime} \mathrm{A}$ and $\mathrm{B}=\mathrm{A}^{-1} \mathrm{~A}^{\prime}$, the $\mathrm{BB}^{\prime}$ equals :

1. $\mathrm{I}+\mathrm{B}$

2. I

3. $\mathrm{B}^{-1}$

4. $\left(\mathrm{B}^{-1}\right)^{\prime}$

Correct Option: , 2

Solution: