The homework question asks: which work woulf be required to stop a moving object: the intial speed, the intial kinetic energy of the object, the mass of the object times it acceleration, the mass of the object times its intials speed, or the square of the intial speed of the object.

Since you said its based on change in KE, The work required to stop the car would be intial KE

Thank you

The work done on friction is equal to the initial KE of the object.

You are correct.