Answer:
The correct option is:
D) starting to move and then increasing speed
Step-by-step explanation:
The speed of the racehorse is given by the slope of the given Distance-time graph.
Speed = Distance/time = Slope of the graph
The slope of the graph keeps increasing.
Hence, the speed of the racehore is increasing.
The distance moved is zero at t=0. Hence, the racehorse has started to move from rest.