Answer: Option E. "Fatty Acid"
Explanation:
Fatty acid is an important component of lipids present in animals, plants and microorganisms.
A fatty acid consist of a straight chain that involves a long hydrocarbon chain (Carbon and hydrogen atoms) and at the other end, a carboxyl group (―COOH) is present. Carboxyl group is responsible for the acidic nature of fatty acid.
If the bonds between carbon-to-carbon are all single, the acid is called saturated; if there are double or triple bonds, the acid is called unsaturated and is most reactive.
Hence, the correct option is E.