Sentence Correction

Several years ago the diet industry introduced a variety of appetite suppressants, but some of these drugs caused stomach disorders severe enough to have them banned by the Food and Drug Administration.
(A) stomach disorders severe enough to have them
(B) stomach disorders that were severe enough so they were
(C) stomach disorders of such severity so as to be
(D) such severe stomach disorders that they were
(E) such severe stomach disorders as to be


I get that D is the answer.

but what's wrong with A?

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