单项选择题Fuel oil transfer systems used onboard diesel propelled vessels are required to have ().
A.two fuel oil transfer pumps provided where one is to be independent of the main engine
B.two fuel oil transfer pumps, with a combined capacity exceeding the maximum consumption of the main engine
C.engine driven transfer pumps and only used in constant speed applications
D.the capacity of the engine driven pump exceed the consumption rate of the engine to which it is attached