Regulations require that tankers handling grade B liquids shall have their cargo pumps separated from all sources of vapor ignition by（）.

A.cofferdams
B.empty cargo spaces
C.gas tight bulkheads
D.areas equipped with power ventilation

A.power ventilation
B.gooseneck vents and flame screens
C.at least two ducts extending to the weather deck
D.a vent header system

A.gooseneck vents and flame screens
B.pressure-vacuum relief valves
C.branch vent lines and a vent header
D.forced draft blowers