— Where is Lucy, Jane? 

— I am not sure. _____. [ ]

A. She must have gone home

B. She can't have gone home

C. She should have gone home

D. She might have gone home

距离保护中阻抗继电器，需采用记忆回路和引入第三相电压的是（）。

A.全阻抗继电器；

B.方向阻抗继电器；

C.偏移特性的阻抗继电器；

D.偏移特性和方向阻抗继电器。