How did shi huangdi impose allegiance to a central government? a. by replacing feudal states with military districts run by loyal officials b. by appointing confucian scholars to run his administration c. by establishing a civil service system in government d. by establishing trade routes along the silk road

There are a number of things that Shi Huangdi did to impose allegiance to a central government, and here are some of them:
- abolished feudalism
- replaced feudal states with military districts run by loyal officials
- gave nobles' lands to peasants
- forced noble families to live at court
Based on this, I would pick A as the correct answer.