786. The National Transportation Safety Board has recommended the use of fail-safe mechanisms on airliner cargo door latches assuring the doors are properly closed before takeoff and to prevent them from popping open in flight.
(A) assuring the doors are properly closed
(B) for the assurance of proper closing
(C) assuring proper closure
(D) to assure closing the doors properly
(E) to assure that the doors are properly closed

IMO, the first of the sentence need to be parallel with "to prevent them from popping open in flight" so I would go with:

(D) to assure closing the doors properly

what is the OA ?

EE2009

OA is E

this doesn't appear to be a gmatprep problem. not only is the style noticeably different from that of most official problems, but there's the problem of that "786" out front (which would not be there if this were an official problem).

i'm moving this thread to the general verbal folder; we will delete it in a few days if you don't post the SOURCE of this problem. thank you.