Which statement best describes the purpose of a fuel oil heater in a marine diesel system?

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Fuel oil heaters are used to raise the temperature of the fuel so its viscosity drops, allowing proper atomization when it’s injected into the cylinder, especially during startup in cold conditions. Heating the fuel prevents the waxes in some fuels from crystallizing (gelation), which can clog filters and hinder injection. This ensures a reliable fuel spray, smoother starting, and consistent combustion.

The other options describe heating systems for different fluids, not the fuel used by the injectors: lubricating oil for bearings, coolant water for engine cooling, and air for combustion.