Which of the following represents a ketone in organic compounds?

A ketone is characterized by the presence of a carbonyl group (C=O) bonded to two carbon atoms. In this context, the representation R-CO-R' reflects this structure, where R and R' are hydrocarbon chains or groups. The carbonyl carbon is flanked by two alkyl groups (R and R'), distinguishing ketones from other functional groups.

The choice R-CHO corresponds to an aldehyde, where the carbonyl group is located at the end of the carbon chain and is bonded to a hydrogen atom. R-COOH represents a carboxylic acid, which has both a carbonyl and a hydroxyl group (-OH) on the same carbon atom. R-C≡C-R' denotes an alkyne, which features a triple bond between carbon atoms and does not contain a carbonyl group at all.

Thus, the representation R-CO-R' is the only one that accurately depicts a ketone, highlighting it as the correct choice.