Here's a problem to solve: Acid rain has a pH below 5.6. This rain can damage soil, lakes, crops, and buildings. Acid rain is caused by all of the following except

Among the 4 following options, which is the correct answer?

- A: industrial emissions from factories.
 
- B: coal that is burned to produce heat and power.
 
- C: automobile exhaust.
 
- D: nuclear power plants that produce radiation.
 