In the Twentieth Century the Supreme Court Became Increasingly More

In the twentieth century the Supreme Court became increasingly more willing to protect individuals against intrusive state actions. What instrument gave the Supreme Court this authority?

A) The Civil Rights Act of 1871
B) The Alien and Sedition Acts
C) The First Amendment, which guaranteed freedom of speech
D) The Fourteenth Amendment, which guaranteed due process of law by the states
E) The free exercise clause