Given that :
The object in a simulation accelerates from rest to a speed of 4 meters per second in 2 seconds.
So, from t = 0 to t = 2 seconds, the graph will rise.
It then accelerates linearly for the next 3 seconds until it reaches 10 meters per second.
So, from t = 2 to t = 5 seconds, the graph will be a straight line going upwards.
The object remains at that speed(acceleration = 0) for 3 seconds.
So, from t = 5 to t = 8 seconds, the graph will be a horizontal line.
It then de-accelerates linearly until it comes to rest 2 seconds later.
So, from t = 8 to t = 10 seconds, the graph will be a horizontal line coming downwards.
The graph that follows the above trends is D.
Thus, graph D is correct.