取无穷远处电势为零,关于两个等量异种点电荷的连线中点的场强和电势,下列说法中正确的是( )
A:场强为零,电势不为零
B:场强不为零,电势也不为零
C:场强不为零,电势为零
D:场强为零,电势也为零
When you are sick, you should a doctor.