因此我很遗憾地通知您 我们不能接受您退款的要求。()

因此我很遗憾地通知您，我们不能接受您退款的要求。()

A.I regret to inform. you, therefore, that we cannot give you a refund.

B.Therefore, I am pleased to inform. you that we cannot give you a refund.

C.I regret to inform. you, therefore, that we can give you a refund.

D.Therefore, I regret to inform. you that we cannot accept your request.

请帮忙给出正确答案和分析，谢谢！