For `3 xx 3` matrices M and N, which of the following statement(s) is/are not correct?

Options

A. `N^T MN` is symmetric or skew-symmetric, according as M is symmetric or skew-symmetric
B. MN-NM is symmetric for all symmetric matrices M and N
C. MN is symmetric for all symmetric matrices M and N
D. (adj M) (adjN) = adj(MN) for all invertible matrices M and N

Answer

C, D