Read the excerpt from "Everest Then and Now." The tourism industry surrounding Everest also impacts the environment. The biggest and most obvious impact is the amount of waste climbers leave behind. I have witnessed it firsthand. More and more waste is left each year. This includes empty oxygen and fuel tanks, abandoned tents, batteries, empty cans, and bottles. The government of Nepal requires each climber to bring about eight kilograms of waste back when they descend the mountain. They also make climbers pay some extra money before they start climbing. This money is only returned if climbers come back with the same amount of equipment they started with. When a climber returns with all of their gear, it means no waste was left on the mountain. In recent years, climbers and guides have removed more than 16 tons of litter from Everest. I have been a part of several expeditions that have climbed partway up the mountain just to clean it up. There are no estimates of how much waste remains on the mountain.

Which detail from the excerpt reveals the impact that humans have had on Mount Everest?

The government of Nepal requires each climber to bring about eight kilograms of waste back when they descend the mountain.
The tourism industry surrounding Everest also impacts the environment.
They also make climbers pay some extra money before they start climbing.
This includes empty oxygen and fuel tanks, abandoned tents, batteries, empty cans, and bottles.