Fuels as produced in a refinery are generally sterile; however, contamination can occur as fuels are __________.

Correct Answer: Option D — All of the above are correct.

Fuel contamination by microorganisms is a pervasive issue throughout the supply chain. Because fuel is sterile at the refinery, contamination occurs during storage, transit via tankers or pipelines, and final storage on the vessel. Maintaining fuel quality requires rigorous monitoring and purification throughout every stage of the distribution and storage process.