Concept: A fishy smell is a characteristic property of amines.Explanation:Amines are organic compounds derived from ammonia, NH3.Their general formula is RNH2, where R is an alkyl or aryl group.Lower amines have a distinctive fishy or foul smell.Other classes like amides, RCONH2 or RCONHR1, and ketones, RCOR1, do not share this fishy odour.Answer:C.RNH2