The outlet from an expansion tank of a closed fresh water cooling system should be piped to the __________.

Correct Answer: Option C — jacket water pump suction line

The expansion tank in a closed fresh water cooling system must be connected to the pump suction line to maintain a positive head pressure. This prevents cavitation at the jacket water pump impeller and ensures the system remains pressurized, which helps prevent air pockets and boiling within the engine cylinder jackets.