Final answer:
The question is most likely referring to 'moles of water' as the product of the complete combustion of a hydrocarbon, measured in the amount of 7.2 units.
Step-by-step explanation:
The question addresses the product of the complete combustion of a hydrocarbon, specifically asking what is produced in the amount of 7.2 units. The options given include ATP molecules, moles of water, kilocalories of energy, and grams of carbon dioxide.
Given the context from the provided excerpts, the most fitting answer appears to be 'moles of water' since the combustion of hydrocarbons typically produces water and carbon dioxide, and energy content is often measured in kilojoules or kilocalories.
However, without a specific hydrocarbon or complete reaction provided, the answer remains an educated guess based on typical combustion reactions.