—These days all China is worried about the plane of MH370.

—Yes. All the world wants to know________________.

A．where did the plane go

B．where did the plane landed

C．if the passengers are alive

D．when can we find the plane

某蓄水池有一进水口A和一出水口B，池中无水时，打开A口关闭B口，加满整个蓄水池需2小时；池中满水时，打开B口关闭A口，放干池中水需1小时30分钟。现池中有占总容量1/3的水，问同时打开A、B口，需多长时间才能把蓄水池放干？（）

A．90分钟

B．100分钟

C．110分钟

D．120分钟