challenge: What was Yoshihiko Yoshimatsu's achievement at the 1956 World Judo Championships in Tokyo?
  
  A. He received a bronze medal, behind Shokichi Natsui and another judoka
  B. He won the gold medal, defeating Shokichi Natsui
  C. He did not participate in the championships
  D. He received a silver medal, behind winner Shokichi Natsui
  Answer: 