Answer:
He stoped on 3th quarter,i.e, $C$.
Explanation:
He ran 105 full circles ( 5280/50=105 ( rst= 30ft) ). So in the last circles he started from point S to run 30ft more.
The quarter of the circle is long 50ft/4= 12,5ft. So for 30 feets he must run 2 quarters, its 25ft. The last 5ft he ran on the 3th quarter, so he stoped on C.
This answer $C$, if $C$ is the 3th quadrant, i don't see the picture of the track.