Directions: In this question, a sentence has been divided into four parts (A), (B), (C), (D). Read the sentence to find out whether there is any grammatical error in it. The error, if any, will be in one part of the sentence. Mark that part as your answer. If there is no error, the answer is 'No error'. Ignore the error of punctuations if any.

He has been  (A) / toiling hardly (B) /  to be able to  (C) / provide for his family. (D)