Identify the part of the sentence that contains a grammatical error: 'Neither of the two (A) / proposals were approved (B) / because the committee found (C) / both of them to be unsatisfactory. (D)'

Identify the grammatically or contextually INCORRECT sentence among the following options.

Identify the part of the sentence that contains a grammatical error: 'He is (A) / not only intelligent (B) / and hardworking, (C) / but also very kind. (D)'