血培养皮肤消毒的“三步法”是指（）

血培养皮肤消毒的“三步法”是指（）
A.75%乙醇30s,10%碘伏60s,75%乙醇60s(正确答案)
B.10%碘伏60s,75%乙醇30s,75%乙醇30s
C.75%乙醇30s,75%乙醇30s,10%碘伏60s
D.异丙醇30s,75%乙醇60s,75%乙醇30s