关于肺结核对妊娠的影响，下列哪项是错误的：

A.肺结核患者除非同时患有生殖器结核，一般不影响受孕 

B.非活动性肺结核病变范围不大，对妊娠经过和胎儿发育影响不大 

C.活动性肺结核患者妊娠，可致流产、胎死宫内 

D.严重肺结核合并妊娠，围产儿死亡率可高达30％～40％ 

E.结核病孕妇在产前不会将结核菌传给胎儿 

----Which is _______ to understand, this book or that book?

---- I think both of them are quite easy.

A．difficult

B．more difficult

C．the most difficult

D．much too difficult