Answer :
Answer: A car is accelerating when it is traveling on a straight uphill road at 30 miles per hour.
Explanation:
Acceleration is the change in velocity of an object with respect to time. For a body to accelerate, its velocity must be changing at every time interval. According to option a and c, the velocity of the body is constant during the journey but the time is changing. A body with constant velocity possesses a zero acceleration.
A car travelling on a straight up hill possesses velocity change at each time interval. Since the car is on a slope, its shows its acceleration is changing.