In the 1963 case Gideon v. Wainwright, the U.S. Supreme Court ruled in favor of the defendant, Clarence Earl Gideon. They ruled that because he was indigent, the court was required to pay for a lawyer to defend him. What constitutional right did this confirm?

The Sixth Amendment right to a speedy and public trial.
The First Amendment right to free speech.
The Fifth Amendment right to due process.
The Sixth Amendment right to assistance of counsel.