A variable capacitor is inserted in a line to check the positioning piece length. If the positioning piece is too long, after adjusting the capacitor for minimum reverse power:

A$.$ the reverse power can be reduced to zero.

B$.$ there will be an $E_{\text{m}\text{i}\text{n}}$ point at the point of attachment.

C$.$ there will be an $E_{\text{m}\text{a}\text{x}}$ point at the point of attachment.

D$.$ the capacitance of the stub will be zero.