Thoreau’s actions in "Civil Disobedience" and the 1955 bus boycott are similar because both Thoreau and the boycotters were protesting unjust government policy in a peaceful way. Option D is correct.
On the one hand, the boycott protested againts racial segregation.
On the other hand, Thoreau refused to pay taxes in an attempt to protest the government's involvement in wars and their lack of efficiency in addressing some other injustices.