#### Answer

They All Finished (the curves all reached 100m on the y-axis):
First: A
Second: B
Third: C
What this graph tells us:
- A had a slow initial acceleration, which increases along its path, hence a greater top seed which is able to place 1st
- B had the fastest initial acceleration but slowed down and came to a stop somewhere in the middle of the race hence their 2nd place.
- C Had the second greatest initial acceleration, which decreases along the middle and increases again a bit at the end, coming 3rd.

#### Work Step by Step

It is relatively straightforward to determine who came first, by looking at which point at y = 100m has the lowest x-value (meaning they finish in the lowest time), and that is A.
Looking at the graph of A, the line curved up, which indicated that A was accelerating, and the top speed can be determined by the gradient at ~10s, which was the steepest point, and hence the highest rise/run or m/s. This top speed was higher than the curve C, and was enough to surpass C at ~11s. However, we cannot tell (without values) if the top speed of A was higher than the top speed of B, but because B stopped during the 3-15s period (as the gradient was a constant 0 {hence 0 m/s}), A was still able to surpass the graph of B when it was stationary.
This is just a mere explanation using Calculus - but the observations can still be determined by just studying the graph logically.