Methyl nitrile is hydrolyzed to carboxylic acid in the presence of \(H_3O^+\) as catalyst. An intermediate compound \([A]\) is formed during this reaction.

The sweet smelling compound [D] is:

Ester

The correct answer is option 4. Ester.

The sweet smelling compound is an ester. The reaction will be as follows:

Let us look at the mechanism of formation of ester from carboxylic acid i.e., acetic acid