When forming a cyanohydrin from acetone, how does HCN function in the reaction mechanism?

• A. HCN provides CN- which acts as a nucleophile and also donates a proton to stabilize the intermediate.
• B. HCN acts solely as a solvent for the reaction.
• C. HCN deprotonates acetone to form an enolate intermediate.
• D. HCN oxidizes acetone to form the cyanohydrin.

Answer: (A)