Question 3255 Deck General

The correct answer is C) 11. When filling fuel-oil tank 4S on the DEEP DRILLER, it is necessary to open valve 11. This is because valve 11 is the valve that controls the flow of fuel to tank 4S. Opening this valve allows the fuel to be pumped into the correct tank during the refueling process. The other answer choices are incorrect because they refer to different valves that control the flow of fuel to other tanks or systems on the vessel, and would not be the appropriate valve to open when filling tank 4S.