Answer:
3
Explanation:
3 visually has the greatest slope Distance / time = greatest speed...
Here are the speeds (as I read the graph, always double check my work)
1) is 10m / 4s 2.5 m/s
2) is 15m / 4s 3.75 m/s
3) is 30m / 2s 15 m/s
4) is 5m / 4s 1.25 m/s