换药室里物体表面的细菌监测标准（）。

A．≤5cfu/m²

B．≤10cfu/m²

C．≤15cfu/m²

D．≤200cfu/m²

E．≤500cfu/m²

-I'm sorry. That wasn't of much help.

- ________. In fact, it was most helpful.[ ]

A. Thanks anyway    

B. It doesn't matter    

C. Of course not        

D. Sure it was