Answer:
D. Roads unified the empire and made it easier for the army to stop rebellions
Step-by-step explanation:
The network of public Roman roads was very vast that helped them in free movement of goods, people, and armies.
The network of roads indirectly helped unify the empire with several cultures and races. Before road formation, Robbers or rebellions could easily hide or run but after the development of roads, it became easy to stop rebellions and move their troops around quickly.
Hence, the correct answer is "D. Roads unified the empire and made it easier for the army to stop rebellions."