设 $A, B$ 为 $n(n \geqslant 2)$ 阶矩阵, 则下列说法中, 错误的是
$\text{A.}$ $\left(\begin{array}{ll}A & O \\ O & B\end{array}\right)$ 与 $\left(\begin{array}{ll}B & O \\ O & A\end{array}\right)$ 相似.
$\text{B.}$ $\left(\begin{array}{ll}\boldsymbol{O} & \boldsymbol{A} \\ \boldsymbol{B} & \boldsymbol{O}\end{array}\right)$ 与 $\left(\begin{array}{ll}\boldsymbol{O} & \boldsymbol{B} \\ \boldsymbol{A} & O\end{array}\right)$ 相似.
$\text{C.}$ $\left(\begin{array}{ll}A & O \\ O & B\end{array}\right)$ 与 $\left(\begin{array}{ll}O & A \\ B & O\end{array}\right)$ 相似.
$\text{D.}$ $\left(\begin{array}{cc}A & O \\ O & B\end{array}\right)$ 与 $\left(\begin{array}{cc}A & B-A \\ O & B\end{array}\right)$ 相似.