Question: Which club has the most members majoring in "600"?
SQL: SELECT t1.clubname FROM club AS t1 JOIN member_of_club AS t2 ON t1.clubid  =  t2.clubid JOIN student AS t3 ON t2.stuid  =  t3.stuid WHERE t3.major  =  "600" GROUP BY t1.clubname ORDER BY count(*) DESC LIMIT 1