Concept:Metonymy is a figure of speech where a related word or part is used to represent the whole thing.Explanation:The choir is said to be "on wheels".This actually means the choir is traveling inside a bus or vehicle."Wheels" are only a part of the vehicle.Here, the part is used to represent the entire vehicle.Thus, "wheels" stands for the bus carrying the choir.This substitution of a related term for the object is a clear example of metonymy.Answer:C. Metonymy