The correct answer is C. being alone in nature.
Transcendentalism is a philosophical (and later literary) movement beginning in the 19th century which proposed the idea that the society is bad, and that nature is good. According to transcendentalists, people cannot truly be happy if they are surrounded by buildings and crowds, and that they should reject the society and go into nature to live on their own.
According to them, nature will give them everything they need - a home, sustenance, and most important of all, truth and a meaning.