IF THERE ISN'T ENOUGH RAIN, THE HYDROPOWER STATION CAN NOT OPERATE...

2. If there isn't enough rain, the hydropower station can not operate.

A. Unless there isn't enough rain, the hydropower station can not operate.

B. Unless there is enough rain, the hydropower station can't operate.

C. When there isn't enough rain, the hydropower station can operate.

D. Unless there is enough rain, the hydropower station can operate.