据《汉书．地理志》载：公元前2世纪末，西汉政府先后设置酒泉郡、张掖郡、武威郡和敦煌郡。以上四郡的设置使西汉加强了对哪一地区的控制

A        B       C       D

This is Mr．Smith, ________ I think has something interesting to tell you．

A．who

B．whom

C．that

D．/