The correct answer is - a. Hunting-Gathering.
The Native Americans (Koso, Shoshoni, Ute, Panamit, Paiute, Walapi, Washoe tribes) that lived on the territory of present day Nevada were mainly reliant on hunting and gathering for their survival. This was due to the geography and climate of the state of the area. Consisted of semi-arid mountains, deserts, and the Colorado River Canyon it was not a place were agriculture can be developed, so the people living in here continued to practice the old ways of finding food.