The correct answe gere is B) Carboxylic acidCH3COOH( ethanoic acid, or also cale acetic acid) is a carboxylic acid. This could be justified by the presence of -COOH(carboxylic functional group) in the structure of the molecule Similarly, the student can deduce that B) is the correct answer by exlcuding the other options. Alkenes do not include oxygen atoms in their are charactarised by the presence of double bonds in their structure. Alcohols do have oxygen in their structure, but their functional group iis -OH( hydroxyl group). Ketones also include an oxygen atom in their structure. The functional group here is -C=O (-keto group).