Answer:
Notice that the distance is in the y-axis, and the time in the x-axis.
First, let's see what happens in the four points:
A) You can see that in point A, the steepness of the line increases, this means that the speed of the runner increases in that point.
B) In this point, the runner that increased his/her speed in point A crosses the graph of another runner, this means that they are at the same distance to the end and at the same time.
C) In this point again two runners are at the same distance and the same time, and we also can see that the runer that increased his/her speed at point A, now has reached the end of the race (because his line stops increasing, wich means that he/she already finished the race)
D) The las runner finishes the race at point D.
Then the first runner that finishes the race is the one with the shorter graph (shorter graph means that he ran for less time than the others, wich means that he/she finished first)
The last runner is the one that finished at point D,
The middle one finishes right after the point C.
pounds. 
