gravitational kinetic potential thermal
I gave my students this multiple choice question: Some new cars use special braking systems to recover energy when the brakes are applied. This energy is stored in special batteries and is used to power the electric motor. What type of energy are the brakes storing as they slow down the car?

Only one answer is correct among these 4 choices:
- gravitational
- kinetic
- potential
- thermal

Could you tell me which one is correct?

potential