___his classmates___his Maths teacher has gone hiking. You can’t find them at  school.

A．Both, and

B．Neither, nor

C．either, or

D．Not only, but also

母联兼旁路开关代替线路开关或变压器开关运行时，其保护须按所代开关的保护定值更改后方可代替运行。