You are cleaning the tanks after carrying a cargo of crude oil. Which statement is TRUE? （）
- AWashing water should be recirculated if possible because it has the same electric potential as the cargo tank being cleaned
- BThe hoses to portable cleaning machines should be disconnected before the machines are removed from the tank
- CThe principal hazard with steaming cargo tanks is raising the ambient temperature above the flame point of the cargo residue
- DSteam cleaning and water washing are both capable of generating electrostatic charges within a tank