—What's on the table?

—________ some bread on it. [ ]

A. There is

B. There are

C. We are

D. They are

一个三极管接在电路中，看不出它的型号，也无其它标志，但可测出它的三个电极的对地电位，分别为VA=-9v，VB=-6v，VC=-6.2v，则A端是（）。

A.集电极

B.基极

C.发射极