Answer:
From 0.75 to 1.25 hours
Explanation:
Given
See attachment for graph
Required
Point where they didn't move
This means that we identify the point where the distance didn't change.
Given that the distance is plotted on the y-axis, we simply check for the end points of any horizontal line on the graph
The horizontal line on the graph represents 30km and the time interval is: 0.75 to 1.25 hours.
Hence, (c) is correct