Select the word segment that substitutes (replaces) the bracketed word segment correctly and completes the sentence meaningfully. Select the option 'no correction required' if the sentence is correct as given.

He did exceptionally well in his exams (because he had tutored all week).

A

No correction required

B

as he had tutored all week

C

as he had been tutored all week

D

as he had been tutoring all week