Answer: Choice B (upper right corner)
==========================================================
Step-by-step explanation:
At first the car isn't moving at all. This is at time 0. So this means the graph starts at the origin (0,0). Based on this alone, the answer is either choice B or choice C.
We can rule out choice C because the rates of change won't be constant to give those sharp straight lines. Instead, we have a gradual shift in speeds as the roller coaster progresses. So we'll have more of a curved shape as choice B shows.
Note that each time the car is going downhill, the speed goes up. On the flip side, as the car goes uphill, the speed goes down. So the direction of movement runs counter to the speed graph direction (one goes up, the other goes down).