The correct answer is B. Regenerative braking.
Regenerative braking is a braking system that converts the kinetic energy of a vehicle into electrical energy, which can then be stored in a battery or used to power other electrical systems on the vehicle. This type of braking is often used in electric vehicles, as it allows them to recover some of the energy that would otherwise be lost as heat during braking.
Plugging is a type of braking system that uses the motor to generate a braking force. This type of braking is often used in elevators, as it allows them to come to a smooth stop. However, it can also be used in other types of vehicles, such as trains.
Rheostat braking is a type of braking system that uses a resistor to dissipate the kinetic energy of a vehicle. This type of braking is often used in older vehicles, as it is relatively simple and inexpensive. However, it is not as efficient as other types of braking systems, such as regenerative braking.
None of the above is not a correct answer.