Answer:
D.
EPLAINATION
Alexis de Tocqueville's concern for liberty had to do with personal liberties -- with freedom of conscience and belief being protected in a constitutional republic. By respecting the rights of the Amish to exempt themselves from the Social Security system, the government of the United States is allowing them to have liberty of their beliefs. They don't pay into the Social Security system, and also do not receive benefits from it. They choose to care for themselves and one another in the Amish community.
Alexis de Tocqueville's famous work was published in the 1830s. Based on his travels in the early United States, he wrote Democracy in America, in which he detailed how a democratic society functions.