Read the sentence below to find out whether there is any grammatical error in it. The error, if any, will be in one part of the sentence. Choose the option with that part as your answer. If there is no error, choose 'D' as your answer. (Ignore the errors of punctuation, if any).

Unless you stop to make noise at once, I will have no option but to bring the matter to the attention of the police.

A.

Unless you stop to make noise at once,

B.

I will have no option but to

C.

bring the matter to the attention of the police.

D.

No error.

Correct answer is A

Unless you stop making noise at once