What are the products of the combustion of a hydrocarbon? carbon and oxygen carbon dioxide and water carbon and hydrogen carbon dioxide and hydrogen

Well, there are two types of combustion; incomplete and complete.

Complete gives off: - Water vapour (always)

- Carbon dioxide (always)

Incomplete gives off: - Water vapour (always)

- Carbon dioxide (depends)

- Carbon monoxide (depends)

- Soot (depends)

Incomplete combustion varies, so its products can't always be easily determined. However, water vapour is always produced.

Given your answers, I would go for "carbon dioxide and water"