OA is D.
I will go with D, as well.
754. The financial crash of October 1987 demonstrated that the world’s capital markets are integrated more closely than never before and events in one part of the global village may be transmitted to the rest of the village—almost instantaneously.
(A) integrated more closely than never before and - we need "ever" instead of "never", and "that" after "and"
(B) closely integrated more than ever before so - badly constructed
(C) more closely integrated as never before while - no good
(D) more closely integrated than ever before and that - nice one
(E) more than ever before closely integrated as - out