385. On an Lng tanker during the initial stage of cooling down operation, prior discharging why is it necessary to open the main loading valves of the forward and the aft cargo tanks?

A. to ensure liquid flow into the forward and aft cargo tanks
B. to increase the pressure in the cargo tanks before discharging
C. to clean anhy impurities in the pipelines before discharging
D. to purge the vapor which remains at both ends of the liquid header