Here's a problem to solve: When gasoline in a car engine is burned, only about 15 percent of the gasoline is converted into mechanical energy. This is because most of the energy in the gasoline is

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

- A: transformed into heat.
 
- B: stored for use at a later time.
 
- C: changed into chemical energy.
 
- D: used to make the vehicle move.
 