fireworks display glowing light stick first-aid instant cold pack gasoline-burning car engine
I gave my students this multiple choice question: Which of these is an example of an endothermic process?

Only one answer is correct among these 4 choices:
- fireworks display
- glowing light stick
- first-aid instant cold pack
- gasoline-burning car engine

Could you tell me which one is correct?

first-aid instant cold pack