19. Aviation officials have not only failed to determine the cause of the crash, but they have also ignored demands by the pilots union that the investigation should be expedited.>>
(A) crash, but they have also ignored demands by the pilots union that the investigation should be expedited>>
(B) crash but also ignored demands by the pilots union that the investigation be expedited>>
(C) crash but have ignored demands for expediting the investigation by the pilots’ union>>
(D) crash, but they are also ignoring the pilots’ union’s demands to expedite the investigation
(E) crash: the demands by the pilots’ union that the investigation should be expedited have also been ignored>>
想问下这里的c如果改成：
crash but ignored demands for expediting the investigation by the pilots' union
是不是对的呢？ | 
