Consider the following materials : 1. Agricultural residues 2. Corn grain 3. Wastewater treatment sludge 4. Wood mill waste Which of the above can be used as feedstock for producing Sustainable Aviation Fuel ?

Option (c) is correct because Sustainable Aviation Fuel (SAF) can be produced from a broad spectrum of renewable sources, including lignocellulosic biomass (agricultural and wood waste), starch-based crops (corn grain), and organic waste like wastewater sludge. Option (d) is the most tempting distractor as candidates often assume food crops like corn are excluded due to "food vs. fuel" concerns, but corn remains a primary feedstock for the Alcohol-to-Jet (ATJ) production pathway. The core concept tested is the technical eligibility and diversity of feedstocks for SAF production under global carbon reduction frameworks.