Which sequence of reactions would you use to protect an aldehyde group in a multi-step synthesis and then regenerate it at the end?

• A. Convert the aldehyde to a ketone, perform reactions, then convert back to an aldehyde.
• B. Oxidize the aldehyde to a carboxylic acid, perform reactions, then reduce back to an aldehyde.
• C. Form an acetal, carry out the desired reactions, then hydrolyze the acetal.
• D. Dehydrate the aldehyde, perform reactions, then rehydrate to form the aldehyde.

Answer: (C)