The inca travel long distances and communicate with their neighbors

Rope bridges is the answer.

Explanation:

Inca Empire, also known as the Incan Empire and the Inka Empire was the largest empire in the pre-Columbian America. Cusco was the most important city since it was the administrative, political, and military center.

Inca rope bridges are suspension bridges over canyons and rivers built by the Inca Empire. They were part of the Inca road system and it's a proof of Inca innovation and engineering and they were very helpful since Inca people didn't use wheeled transport.

just like you man, i personally think its either c or d

explanation:

but good luck with the test man

your answer would be just capitalism.