Crotonyl alcohol is an unsaturated alcohol with the structure where the alcohol group (-OH) is attached to the terminal carbon of the butene chain. The correct structure is CH\(_3\)-CH=CH-COH, where the hydroxyl group is bonded to the -CH\(_2\) group at the end of the chain, and the molecule has a conjugated system with a double bond between the second and third carbons.
- Option (A) is incorrect as it represents crotonic acid, not crotonyl alcohol.
- Option (B) is incorrect because it has the wrong functional group (hydroxyl group on the aldehyde).
- Option (D) is incorrect as it represents 3-buten-1-ol, not crotonyl alcohol.
Therefore, the correct answer is option (C).