Two Classes of Explanations, Imperfect Information and Sticky Prices or Nominal

Two classes of explanations, imperfect information and sticky prices or nominal wage contracts, have been advanced to explain the phenomenon we call price rigidity. Which of the following statements regarding price rigidity is not correct?

A) Both are necessary for a complete understanding of price rigidity.
B) Price rigidity determines, to a large extent, the efficacy of monetary policy.
C) Microeconomic underpinnings such as these help clarify the effects of monetary policy.
D) Macroeconomists disagree about the relevance of price rigidity to effective monetary policy.
E) All of the above statements are correct.