Cup on fire

Classical Mechanics Level pending

You have a paper cup filled with water and you heat the bottom with the flame from a bunsen burner. What happens to your system?

Assumptions

We are thinking about the period in which the cup still contains water (it hasn't all been lost due to evaporation, or some other process).

The water boils and the cup stays intact. The water heats up a little until the cup catches fire. The water absorbs all the heat and the flame goes out. The water stays at the same temperature and the cup catches fire and the water falls out.