Answer: 11 runners
Look at the histogram. You can see that 3 runners finished the race between the 34.5 and 39.5 minute mark. The other 8 runners finished between 29.5-34.5 minutes.
Based on this your answer would be choice B - 11 runners.
Hope that helps! ★ If you have further questions about this question or need more help, feel free to comment below or leave me a PM. -UnicornFudge aka Nadia