You are planning to use the crude oil washing system on your tankship. What is required to prevent electrostatic buildup in the tanks?

A
The portable machines should be set at the proper drop for the first wash before the fixed machines are used.
B
The tank used as the source for the tank cleaning machines should be debottomed for at least one meter.
C
The inert gas system must reduce the oxygen content in the tank to at least 18%.
D
The fixed machines must be operated simultaneously with the portable machines to equalize the electrostatic potential.
E