Which statement is true about the mongol empire after genghis khan’s death? a.  batu khan had more tributary states than kublai khan. b.  kublai khan’s empire was larger than batu khan’s empire. c.  kublai khan unified china, and batu khan unified most of russia. d.  kublai khan and batu khan were equally successful as conquerors. e.  kublai khan had more tributary states than batu khan.