请教GWD第22套一道语法题

hujing92

The soft drink company's flat earnings for the second quarter reflect the success of both its restructured global bottling system and the extent to which poor currency exchange rates keep down profits for multinational companies
A.reflect the success of both its restructured global bottling system and the extent to which poor currency exchange rates keep
B.reflect both the success of its restructured global bottling system and the extent to which poor currency exchange rates are keeping
C.reflect both the success of its restructured global bottling system and the extent of poor currency exchange rates keeping
D.both reflect the success of its restructured global bottling system and to what extant poor currency exchange rates are keeping
E.both reflect the success of its restructured global bottling system and to what extent poor currency exchange rages are keeping

正确答案B
请问A怎么错的？

HarrisZheng

the success of the extent to which poor currency exchange rates keep down profits for multinational companies 不make sense