Which best states the overall structure of Walden?
A.The work describes the effect spending time in nature has on Thoreau, and then explains why it has that effect.
B.The work describes Thoreau’s thoughts over the course of a year spent immersed in the natural world.
C.The work compares Thoreau’s thoughts before coming to Walden to his thoughts afterward.
D.The work shows how various problems Thoreau had before he came to Walden are solved by his retreat.