Read each sentence to find out whether there is any grammatical or idiomatic…

Read each sentence to find out whether there is any grammatical or idiomatic error in it. The error, if any, will be in one part of the sentence. The letter of that part is the answer. If there is ‘No error’, the answer is (e). (Ignore errors of punctuation, if any).

The cell’s nucleus is like (A)/ the conductor of a huge (B)/ opera who tell all the (C)/ performers what to do (D)/.