--- May I visit you at 10 o’clock tomorrow morning?

--- I’m afraid I ______ a document for my boss then. What about 12:00?

A．am preparing

B．will have prepared

C．will be preparing

D．have been preparing

从哪年，赛龙舟被列入中国国家体育比赛项目，并每年举行“屈原杯”龙舟赛。