The correct answer is A
The civil service provided stability to the Han Empire for over 2,000 years. ITs employees were called mandarines, that needed to be able and honest men and who receive training in order to become competent for the job. It was an important effort for establishing a meritocracy.
One of the requirements was that an official could not serve in his home district. It was a further step in their training, as they could accumulate more knowledge about the empire, its functioning, different conviving social environments and cultures.