—Who will become the team member of the City Cup Final，Lionard or Jack?

—Oh，       ．

A．each

B．no one

C．none of them

D．possibly both

必要条件假言命题只有在哪种情况下才是假的（）？

A、前件真后件假

B、前后件都真

C、前件假，后件真

D、前后件都假