All three statements regarding maize are correct, reflecting its versatility as a crop. Maize is a significant source of starch, which is vital in various food products and industrial applications. Additionally, the oil extracted from maize can indeed be converted into biodiesel, positioning it as an alternative energy source. Furthermore, maize fermentation is a traditional method for producing alcoholic beverages, including beer and other spirits. This multifaceted utility of maize aligns with agricultural practices and biotechnological advancements, which are essential topics in the UPSC examination context, emphasizing sustainable development and food security.