That’s a little bit tricky because it’s close to being the right answer. Yet it’s not “heat” that you need, but an ignition source (a flame or spark).
Here’s what we say in Unit 1 of the Gas module: But all gas fuels work the same way because they all obey the Fundamental Law of Gas Appliances: If you have good fuel flow that meets a good ignition source, you will have flame.
Does that clarify it for you?
P.S. Glad that you are going over your quiz/exam results and thinking about the answers!