I posted a rather straightforward question earlier that requires a good understanding of force, acceleration, and velocity in one-dimension. I asked readers of this blog to post a comment as to the answer to that mechanics question.
The answer is F, which means that all three scenarios are possible.
The question was taken from a physics education research paper with the above title, which you should be able to access for free. It has other questions on similar level that you might want to take a look. In fact, if you are an intro physics student, you might want to test your understanding by reading this paper and see how your understanding (or lack of it) is a serious topic of study.
Actually, if one understands the force, acceleration, and velocity at every part of the trajectory of a simple spring-mass system, one would see that the car-on-the-hill problem is no different.