Correct answer choice is :
A) Region C
Explanation:
By the time of Muhammad’s death in 632, Islam had become a powerful power in the Arabian land. Muhammad’s successors were elected by the Muslim society to carry out the authority and command of Islam throughout the Arabian land and other parts of the world. The four caliphs were more federal forms than religious leaders. By military force, the first caliph, Abu Bakr, took all the classes in the Arabian land under the government of Islam. These tribes had been cut after Muhammad’s death.