The correct answer is C) Thoreau would not support a corrupt government.
The main idea of the bolden paragraph is "Thoreau would not support a corrupt government."
The excerpt clearly reads: "Thoreau believed that a government that supported slavery was corrupt and immoral." That is why he decided not to pay taxes for a number of years.
Henry David Thoreau (1817-1862 was an American journalist and writer and abolitionist, famous for his book "Walden" and his critical essay "Resistance to Civil Government" or "Civil Disobedience," in which he calls the people to resist questionable government decisions in a pacific way. His call to action on civil disobedience influenced many later activists such as Gandhi and Martin Luther King Jr.