The correct option is D Hexanol
Compound H3C−CH2−CH2−CH2−CH2−CH2−OH has 6 carbons in the main chain. Since the root word for a chain with 6 carbons is ‘Hex’ and it has no multiple bonds, the name should be Hexane. Observe the - OH functional group in the compound which is an alcohol. The suffix of alcohols is “ol”. So the name of the given compound is Hexanol.