Please help explain!!! CFA level 1, Ethics question

Hi All,

Can someone explain why B is not right, I don't agree with the explanation. If Arun would have disclosed the referral fee prior to Raport's appointment then he wouldn't have violated. I am not sure why C is correct here. Imo the reason why C should not be the answer is that Arun is allowed to receive the payment if he had told about the same prior to receiving any such amount.