What two developments, C 100-500 CE spurred the development of long-distance trade? a. The building of large, imperial states and the construction of roads and bridges b. The end of tribal warfare and the emergence of salvation religions c. The spread of popular government and the development of navigation technologies d. The emergence of a common currency and the creation of large city-states
The best option from the list would be "a. The building of large, imperial states and the construction of roads and bridges," since bridges were essential in increasing trade efficiency.