You are presented with the question "How does coal produce electricity?" and the following answer choices: 
- It remains dormant
 - It gets cooled
 - By rubbing together
 - chemical reaction
 - It gets heated up
 - major threat to health
 - Through magnetism
 - heat energy

Now knowing that coal is used to produce electricity by burning in coal-fire power stations and heat is essential to the burning process, choose the best answer.


 

     It gets heated up    