Here's a problem to solve: Robert is thinking about buying a new refrigerator. His old refrigerator runs at about 43% efficiency. Which most likely accounts for the remaining 57% of the energy?

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

- A: It is used up by the light in the refrigerator.
 
- B: It is released to the surroundings as heat.
 
- C: It is converted into mechanical energy.
 
- D: It stored as a form of potential energy.
 