For  $3\times 3$ matrices  $P\text{ and }Q$ which of the following statement is(are) not correct?

 $A)\left(Q^{T}PQ\right)=Q^T{P}^T{\left(Q^T\right)}^T=Q^T{P}^{T}Q=Q^{T}PQ$
(or)  $-Q^{T}PQ$, according as $P$ is symmetric (or) skew-symmetric 
  correct.
 $$\begin{gathered} B){(PQ-QP)}^T={\left(PQ\right)}^T-{\left(QP\right)}^T \\ =Q^T{P}^T-P^T{Q}^T=QP-PQ[\because P,Q\text{\hspace{0.17em}\hspace{0.17em}are symmetric}] \\ =-(PQ-QP) \end{gathered}$$
   correct.
 $C){\left(PQ\right)}^T=Q^T{P}^T=QP\ne PQ[\because P,Q\text{\hspace{0.17em}are symmetric}]$
 incorrect.
 $D)\left(adjP\right)\left(adjQ\right)=adj\left(QP\right)\ne adj\left(PQ\right)$
  incorrect.