Fact 1: Afirecracker converts chemical energy into sound.

Fact 2: Fireworks are illegal, including firecrackers.

Given the two facts above, answer the question "What converts chemical energy into sound?" with the following options: 
- a firework
 - sensory neurons
 - Gunshots
 - a bottle
 - a battery
 - animals
 - a flashlight
 - engines


 

 a firework        