In 1849, Henry David Thoreau published Civil Disobedience, in which he argued that citizens have a duty to oppose actions of the government that they feel are unjust. Which actions of the U. S. government motivated Thoreau to take such a stance?

A) the Fugitive Slave Act of 1850

B) the passage of the Chinese Exclusion Act

C) America's imperialist policies and the War with Mexico

D) America's treatment of the Cherokee Indians during Indian removal