Answer:
a. They used the network of roads.
Explanation:
Chaco Canyon was an urban center which was known for her peculiar culture, road network, and various trade activities. History has it that it was initially occupied by the Puebloan's.
After some years, it was abandoned and left desolate because the occupants migrated and interacts with people from other regions.
People far away were able to get to Chaco Canyon by road, due to her good road network.
