单项选择题

直肠癌常规单纯放疗盆腔照射和残存肿瘤局部加量至多少为宜?()

A.45~50Gy,66~70Gy
B.30Gy,66~70Gy
C.40Gy,66~70Gy
D.30Gy,60Gy
E.40Gy,60Gy