It’s _____ hard problem for the twins that ____ of them can work it out.

A．so; neither

B．such a; neither

C．so a; neither

D．such a; none

乙琥胺

A．可引起瞳孔扩大
B．可引起呼吸抑制
C．可引起共济失调
D．可引起急性心力衰竭
E．可引起再生障碍性贫血