Elizabeth's speed increased during the 0 to 5 minute interval
This interval shown on the graph is indicated by the rising line on the vertical axis (y-axis).
The x-axis shows the time intervals graded in 5-minute intervals. the other options shows a flat line (no change in speed) and a downward line (reduction in speed).
The 0 to 5 minute period of her run however is a rising line which means incresing speed.