You are presented with the question "coal is used to produce electricity by burning in inherently modular what?" and the following answer choices: 
- heat
 - stations
 - trees
 - heat energy
 - similar
 - cells
 - adding heat
 - engines

Now knowing that coal is used to produce electricity by burning in coal-fire power stations and coal-fired power stations are inherently modular, choose the best answer.


 

  stations       