The right answer is D. Closing down the dam and draining the reservior
The explanation for this is that in Desert Solitaire, a book written by Abbey, he attacks what he calls "industrial tourism" and development, resulting in national parks (ramps) against the Glen Canyon Dam. In the book, he argues that by closing the dam and draining the reservoir the nature of the site would be restored to its state before human intervention.
Just out of curiosity, Desert Solitaire is considered to be one of the best narratives of the nature of American literature, and has been compared to Aldo Leopold 's The Sand County Almanac and Thoreau Walden.
