Answer: A) zero velocity
Step-by-step explanation:
Recall that the slope is equal to the rise/run.
Rise = change in y = change in distance
Run = change in x = change in time
If we have a horizontal line, then there is no change in y. The rise would be 0 here. The run can be anything you want. Let's just call it x
Slope = rise/run = 0/x = 0
Therefore, all horizontal lines have a slope of 0.
The slope of a distance time graph represents the velocity because
velocity = (change in distance)/(change in time) = rise/run = slope
for example, a velocity of 10 meters per second represents a change of 10 meters over 1 second. The rise here woud be 10 meters and the run would be 1 second.