Read the sentence to find out whether there is any error in it or not. The error, if any, will be in one part of the sentence. The number of that part is the answer. If there is no error, the answer is (5). Ignore errors of punctuation, if any. 

Branson, who has been vocal (A)/ about end modern-day slavery, (B)/ has criticised Saudi Arabia over (C)/ its human rights record. (D)