The correct answer is A) Congress.
The word or phrase that indicates that incorporation was not yet in practice following the ratification of the Bill of Rights is "Congress."
The excerpt says: "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof."
So when the text says "Congress," it meant that it was the branch of the United States government that had the faculty or the decision to make laws. In this case, it was Congress that could have the legal means to make a law and enforce it. But as stated in the Bill of Rights, Congress will never make a law that forces American citizens to profess a specific religion.
