How did henry david thoreau inspire later american reformers?

Henry David Thoreau is best known for "Walden", a book written when he was living for 2 years in a little cottage in a deep forest, and it's about living in nautre. Thoreau also wrote "Resistance to Civil Government" which is about why people shouldn't obey an unfair law. Those two books had a great impact for many later reformers.

Ithink the answer is b.)