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).

I could not convince them because they persisted to suggest that I was lying.

A.

I could not convince them

B.

because they persisted to suggest

C.

that I was lying.

D.

No error.

Correct answer is B

because they persisted in suggesting