Soruyu çözemedim yardım edebilir misiniz?

19. Owing to the recent slump, the staff have been reprimanded for the fact that that they ---- on innovative sales and marketing strategies rather than ---- for things to change. A) should have been focusing / waiting B) must have been focusing / waited C) ought to be focusing / to wait D) would have focused / having waited E) used to focus / to have waited