# 对题目的总结可以通过举例的方式记忆

## 二、解析

1. 满足 B, D 选项的例子：

$$\begin{bmatrix} 1 & \textcolor{red}{0} \\ \textcolor{red}{0} & \textcolor{red}{0} \end{bmatrix} \begin{bmatrix} \textcolor{red}{0} & \textcolor{red}{0} \\ 3 & 4 \end{bmatrix} = \begin{bmatrix} \textcolor{red}{0} & \textcolor{red}{0} \\ \textcolor{red}{0} & \textcolor{red}{0} \end{bmatrix}$$

1. 满足 B, A, D 选项的例子：

$$\begin{bmatrix} 1 & \textcolor{red}{0} \\ \textcolor{red}{0} & \textcolor{red}{0} \end{bmatrix} \begin{bmatrix} \textcolor{red}{0} & \textcolor{red}{0} \\ \textcolor{red}{0} & \textcolor{red}{0} \end{bmatrix} = \begin{bmatrix} \textcolor{red}{0} & \textcolor{red}{0} \\ \textcolor{red}{0} & \textcolor{red}{0} \end{bmatrix}$$

$$\begin{bmatrix} \textcolor{red}{0} & \textcolor{red}{0} \\ \textcolor{red}{0} & \textcolor{red}{0} \end{bmatrix} \begin{bmatrix} \textcolor{red}{0} & \textcolor{red}{0} \\ 3 & 4 \end{bmatrix} = \begin{bmatrix} \textcolor{red}{0} & \textcolor{red}{0} \\ \textcolor{red}{0} & \textcolor{red}{0} \end{bmatrix}$$

1. 满足 B, C 选项的例子：

$$\begin{bmatrix} \textcolor{red}{0} & \textcolor{red}{0} \\ \textcolor{red}{0} & \textcolor{red}{0} \end{bmatrix} \begin{bmatrix} \textcolor{red}{0} & \textcolor{red}{0} \\ \textcolor{red}{0} & \textcolor{red}{0} \end{bmatrix} = \begin{bmatrix} \textcolor{red}{0} & \textcolor{red}{0} \\ \textcolor{red}{0} & \textcolor{red}{0} \end{bmatrix}$$