Answer:
B
Step-by-step explanation:
This is a distance versus time graph. The slope on a given interval gives you speed.
So if the slope is going upwards, the speed is increasing which means it isnt constant
If going downwards, the speed decreasing, which means it isn't constant
If forming a horinzontal line, it has slope of 0, which means that it has a constant speed
The only time speed is constant is at 4.
B is the answer
