Central to the Belief of Twelver Shiism Was the Idea

Central to the belief of Twelver Shiism was the idea that

A) any true believer could be the leader of the Islamic world.
B) the twelfth infallible imam was still alive and would return to spread his faith.
C) Ali had betrayed the prophet Muhammad and therefore his descendants could not rule.
D) there were twelve principle manifestations of Allah.
E) there were Twelve Commandments.