The correct answer is C. benzene.
Methane (CH4) is a simple alkane with a single carbon atom bonded to four hydrogen atoms. Propane (C3H8) is a simple alkane with three carbon atoms bonded to eight hydrogen atoms. Butane (C4H10) is a simple alkane with four carbon atoms bonded to ten hydrogen atoms. Benzene (C6H6) is an aromatic hydrocarbon with a ring-carbon chain structure.
Aromatic hydrocarbons are a type of hydrocarbon that contains a benzene ring. A benzene ring is a six-membered ring of carbon atoms with alternating single and double bonds. The double bonds in a benzene ring are not like the double bonds in other hydrocarbons. They are delocalized, which means that the electrons in the double bonds are shared by all six carbon atoms in the ring. This delocalization makes benzene and other aromatic hydrocarbons very stable.
Benzene is a colorless, flammable liquid with a sweet smell. It is used as a solvent, a fuel, and a starting material for the synthesis of other chemicals. It is also a known carcinogen.