This is an explanation question, and also an "except" question, which tends to make things a bit harder. The passage describes the requirement that wheat flour be supplemented with folic acid so that pregnant women consume more folic acid, thus avoiding birth defects. Four of the choices will describe ways in which the supplementation limits birth defects; we're looking for the one that does not:

(A) This describes a way in which pregnant women who did not consume enough folic acid will start consuming enough.
(B) This choice suggests that the supplementation had a publicity effect that caused people to consume more folic acid.
(C) This is correct. The important thing is that pregnant women consume folic acid, not which wheat flour distributors earn the most business.
(D) This choice shows that supplementing wheat flour helped reach even those women who would not otherwise take recommendations.
(E) This is yet another way in which the supplementation plan helped get more folic acid in the diets of pregnant women.