How many carbon atoms are in propane?

Propane is a hydrocarbon with the molecular formula C₃H₈. In this formula, the subscript '3' indicates that there are three carbon atoms present in one molecule of propane. Each propane molecule consists of three carbon atoms bonded together in a chain, with hydrogen atoms filling the remaining valence electrons of the carbon atoms. This structure is characteristic of alkanes, where each carbon is saturated with hydrogen. Therefore, the correct answer reflects the number of carbon atoms present in propane being three.