Correct Answer:
C. 45m
The correct answer is 45m. In a standard 400m hurdles race, the first hurdle is placed 45 meters from the starting line. The race has a total of 10 hurdles, with the distance between each hurdle being 35 meters, and the final hurdle is placed 40 meters from the finish line.
Options 14.2m and 30m are distances used in other track events (like the 110m hurdles), and 50m is too far from the start.