Which of the following statements is correct regarding the constitutional isomers of $C_5{H}_{12}$?

• A. There are four structural isomers of $C_5{H}_{12}$.
• B. There is only one possible structural isomer of $C_5{H}_{12}$.
• C. There are exactly three structural (constitutional) isomers of $C_5{H}_{12}$.
• D. There are only two structural isomers of $C_5{H}_{12}$.

Answer: (C)

Verified step by step guidance

1. Understand that the molecular formula C\_5H\_12 corresponds to alkanes with five carbon atoms and only single bonds, known as pentanes.
2. Recall that constitutional (structural) isomers differ in the connectivity of atoms, meaning the carbon skeleton can be arranged differently to form distinct compounds.
3. List all possible unique carbon skeletons for C\_5H\_12: a straight chain (n-pentane), a chain with one branch of one carbon (isopentane or methylbutane), and a chain with a more branched structure (neopentane or dimethylpropane).
4. Count these unique structures to determine the total number of constitutional isomers for C\_5H\_12.
5. Conclude which statement is correct based on the number of these isomers identified.