The Primary Criticism by Keynesians of the Credibility Argument for Rules

The primary criticism by Keynesians of the credibility argument for rules is that

A) reputations are a less costly method of gaining credibility.
B) reputations are a less costly method of maintaining credibility.
C) the cost of losing flexibility over policy choices may exceed the cost of gaining credibility.
D) rules that reduce presidential and congressional influence over monetary policy could ultimately be harmful to the economy.