What Was the Major Cause of the Maji Maji Revolt

What was the major cause of the Maji Maji Revolt in German East Africa?

A) Germans would not allow an alliance of small chiefdoms.
B) Native farmers were forced to plant cotton, which depleted soil and returned little profit.
C) After a vision, Kinjekitile promised victory over the Germans.
D) Believing that their holy pool would destroy bullets, the native people rebelled against the Germans.
E) Native people were prevented from participating in local government.