The correct answer is: Ethanol.
Ethanol is a type of alcohol that is made from plant materials, such as corn or sugarcane. It is a renewable resource and can be used as a fuel in automobiles. Ethanol is mixed with gasoline to create a fuel called gasohol. Gasohol is a cleaner-burning fuel than gasoline and can help to reduce emissions from automobiles.
Methanol is another type of alcohol that can be used as a fuel. However, methanol is not as renewable as ethanol and is more toxic. Propanol and butanol are also types of alcohol that can be used as fuels, but they are even less renewable than methanol and are more toxic.
Therefore, the best option for a fuel that is mixed with gasoline for being used in automobiles is ethanol.