一无限长直角电压波从波阻抗为 Z1 的线路传向波阻抗为 Z2 的线路，在连接处发生反射，反射系数为        。

A、<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/9973a61d-3f31-4e59-80fb-6a2b32096841.jpg"title="ex_1257608735422_0.jpg" alt="ex_1257608735422_0.jpg"/>

B、<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/15d025b7-9f4e-4566-a051-4a105cb116ef.jpg"title="ex_1257608748028_0.jpg" alt="ex_1257608748028_0.jpg"/>

C、<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/59cc4b55-1460-431b-a1e4-b2bc9aa04eba.jpg"title="ex_1257608762205_0.jpg" alt="ex_1257608762205_0.jpg"/>

D、<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/d5a5953b-4997-41ab-9818-a6427eda1f90.jpg"title="ex_1257608772398_0.jpg" alt="ex_1257608772398_0.jpg"/>