Directions: In the following question, a sentence is divided into four parts (A), (B), (C), and (D). The error, if any, will only be in one part of the sentence. Choose the option with the part containing the error and mark it, if the sentence is free from errors, mark 'No error' as your answer.

He bought an (A)/ answering machine that (B)/ play back his messages (C)/ when he calls (D)/.