Which detail from the passage best supports the idea that Muir played a pivotal role in

Which detail from the passage best supports the idea that Muir played a pivotal role in the creation of national parks?
A.
Muir encouraged people to write to politicians to protect lands from development.
B.
Muir discovered glaciers and other natural wonders at Yosemite.
C.
Muir wrote books that led more people to be interested in nature.
D.
Muir spoke of the wonder of surviving harrowing conditions at Mount Shasta.