Answer
B.
Work Step by Step
Any enzyme which acts after the block caused by a mutation should still work, so any intermediate which comes after the mutation/block will support growth: B. is correct, and, since it directly disagrees with B., A. is wrong. C. is wrong since feeding the intermediate and producing growth doesn't necessarily say that the affected enzyme is needed, and D. can be eliminated since it also is not necessarily true based on the information given.
