challenge: Why do the natives believe Gil-dong is a safe area to settle?
  
  A. Because of its proximity to the Han River
  B. Because it is geographically located far away from the Han River, making it less prone to storm and flood damage, based on Feng shui Theory
  C. Because of its proximity to Seoul Subway Line 5
  D. Because of the presence of Gangdong Public Library
  Answer: 