What was one reason for Genghis Khan’s success as a military leader?

A.
He ruthlessly destroyed all Mongol clans except his own.

B.
He organized the Mongol Army into an efficient fighting force.

C.
He built goodwill by treating conquered peoples with mercy.

D.
He divided his empire into four military districts called khanates.

B. He organized the Mongol Army into an efficient fighting force.