How Did Zheng, the First Emperor of the Qin Dynasty

How did Zheng, the first emperor of the Qin dynasty, attempt to secure his throne?

A) Zheng had himself appointed emperor by a council of the competing Warring States, ensuring broad support for his reign.
B) Zheng took the title "King of Kings" to emphasize his superiority over lesser rulers.
C) Zheng forced the rulers of defeated states to move to his capital, Xianyang, to ensure that they were not plotting rebellion.
D) Zheng allowed local rulers to retain authority because they could more efficiently collect taxes and put down local rebellions.