Final answer:
The acceleration vector of cars rolling up the ramp can either point upward or downward depending on the specific situation.
Step-by-step explanation:
The acceleration vector of the cars rolling up the ramp depends on the direction of their motion and whether they are slowing down or speeding up.
If a car is moving upward on the ramp and slowing down, its acceleration vector will point downward (choice A) as it is decelerating. On the other hand, if a car is moving upward on the ramp and speeding up, its acceleration vector will point upward (choice B) as it is accelerating in the same direction as its motion.
Therefore, the correct answer is B) Upward or A) Downward, depending on the specific situation.