Which clue can be used to identify a chemical reaction as a combustion reaction?

Question

Oxygen is a product.
A hydrocarbon reacts with oxygen.
Water and carbon dioxide react.
The reaction involves ions.

Answer 1

The clue that can be used to identify a chemical reaction as a combustion reaction is:

A hydrocarbon reacts with oxygen.

In a combustion reaction, a hydrocarbon (which is a compound made primarily of carbon and hydrogen) reacts with oxygen, typically resulting in the production of carbon dioxide and water.