A student draws a distance-time graph for a moving scooter and finds that a section of the graph is a horizontal line parallel to the time axis. Which of the following conclusion is correct about this section of the graph ?
A. the scooter has uniform speed in this section
B. the distance travelled by scooter is the maximum in this section
C. the distance travelled by the scooter is the minimum in this section
D. the distance travelled by the scooter is zero in this section
