which class of organic compound is commonly used in fuels?\n alcohol\n ketone\n alkyl halide\n carboxylic acid

Brief Explanations:

Alcohols are commonly used in fuels. Ethanol, for example, is an alcohol added to gasoline to improve combustion and reduce emissions. Ketones, alkyl halides, and carboxylic acids are not typically used as fuels in the same common - sense as alcohols.

Answer:

alcohol