Which of the Following Statements About the Mechanism of the Addition

Which of the following statements about the mechanism of the addition shown below is true?

A) The transition state for the rate-determining step resembles the starting materials.
B) The addition of chloride anion occurs in the rate-determining step.
C) The reaction proceeds via a concerted mechanism.
D) The addition of the proton is an endothermic step in the reaction mechanism.
E) The HCl acts as the nucleophile in the addition reaction.