已知⊙O₁和⊙O₂的半径分别为3cm和2cm，且O₁O₂=1cm，则⊙O₁与⊙O₂的位置关系为（    ）。

The health official said ______ 12 suspected cases of influenza A (H1N1) were tested  negative and ______, so far, this city has reported no case of the virus.

A．what; that

B．that; what

C．不填; that

D．that; 不填