Step 1: Understand what a carbonyl group is. A carbonyl group is a functional group consisting of a carbon atom double bonded to an oxygen atom: \( \ce{C=O} \) Step 2: Identify which compound has this group. Alcohol has –OH group Amine has \(-\mathrm{NH}_2\) group. Ether has –O– between two alkyl groups Aldehyde has –CHO group, which includes the carbonyl