单项选择题

以下哪项是rBS/WC疫苗(可唯适)的常规免疫程序?()

A.三剂次,0,3,21天各一粒
B.三剂次,0,7,28天各一粒
C.三剂次,0,9,21天各一粒
D.三剂次,0,9,28天各一粒