The correct answer is C. Benzene.
A hydrocarbon is an organic compound that consists only of hydrogen and carbon atoms. Hydrocarbons can be classified as saturated or unsaturated, depending on the number of hydrogen atoms they contain. Saturated hydrocarbons have the maximum number of hydrogen atoms possible for their carbon skeleton, while unsaturated hydrocarbons have fewer hydrogen atoms than the maximum possible.
Benzene is an example of an unsaturated hydrocarbon. It has a molecular formula of C6H6, which means that it contains six carbon atoms and six hydrogen atoms. Benzene is a six-membered ring with alternating single and double bonds. This structure makes benzene chemically reactive, as it can easily undergo reactions that involve the breaking and reforming of the double bonds.
Ethane, butane, and methane are all examples of saturated hydrocarbons. Ethane has a molecular formula of C2H6, butane has a molecular formula of C4H10, and methane has a molecular formula of CH4. These hydrocarbons have the maximum number of hydrogen atoms possible for their carbon skeletons. They are not as chemically reactive as benzene, as they do not have any double or triple bonds.
In conclusion, the correct answer to the question “Which of the following is an unsaturated hydrocarbon?” is C. Benzene.