Corrosion and grooving on the blading of an exhaust driven turbocharger is caused by certain components of residual fuel oils. These components are vanadium, sodium, and __________.

Correct Answer: Option D — sulfur

High-temperature corrosion and grooving on turbocharger turbine blading burning residual fuel are driven by complex chemical reactions involving vanadium, sodium, and sulfur compounds that form corrosive ash deposits.