222. By a vote of 9 to 0, the Supreme Court awarded the Central Intelligence Agency broad discretionary(任意的，自由决定的)powers enabling it to withhold from the public the identities of its sources of intelligence information.

(A) enabling it to withhold from the public

(B) for it to withhold from the public(用不定式，成了目的状语，主语应该是supreme court, nonsense…)

(C) for withholding disclosure to the public of

(D) that enable them to withhold from public disclosure

(E) that they can withhold public disclosure of

Choice A is best: enabling ... clearly modifies powers, it refers logically and grammatically to the Central Intelligence Agency, and to withhold from the public is concisely and idiomatically phrased. In choices B and C, the preposition for is used unidiomatically in place of the "-ing" modifier to introduce the phrase describing powers. In choices C, D, and E, withholding... disclosure is wordy and imprecise, since it is really the identities that are to be withhold. The plural pronouns them in D and they in E do not agree with the singular Agency, and that in E mistakenly introduces a new independent clause rather than a modifying phrase for powers.

为什么it不指代主句主语Supreme Court 而去指代 CIA??

如果指代supreme court意思不通吧。enable的内容应该是修饰powers的 应该是powers 的同位语，而这些powers是赋予CIA的