《中华人民共和国海关法》规定，进出口货物，除另有规定者外，由海关准予注册的报关企业或者有权经营进出口业务的企业负责办理报关纳税手续。 ( )

— How did you do in your essay?

— I got ____ okay grade, but Mr. Jones gave Sarah top marks. She's ____ teacher's pet, you know.[ ]

A. 不填; a

B. an; 不填

C. 不填; the

D. an; a