Which of the rights is most "unique" to the US, with only Mexico, Guatemala, the United Kingdom, and Iran having similar protections in their constitutions?

The correct answer is the very controversial right to bear arms.

The correct answer to this open question is the following.

The right to bear arms is most "unique" to the US, with only Mexico, Guatemala, the United Kingdom, and Iran having similar protections in their constitutions.

The right to bear arms in the United States can be found in the 2nd Amendment of the US Constitution. So every US citizen has the right to bear arms for his protection. Since colonial times, the colonists had weapons that were used to fight the British troops. They possessed weapons because they told that the English Bill of Rights allowed them to do so.