73. When cleaning burner atomizers associated with an oil-fired auxiliary boiler fitted on your fishery research vessel, which of the following metals would be recommended to use in fabricating a tool for the purposes of carbon removal?

Copper is the correct choice because its softness prevents damage to the atomizer's precision surfaces during carbon removal; harder metals like chromoly steel, tungsten, and titanium would scratch or enlarge the orifices, compromising spray pattern and combustion.