Which one of the following is a U.S. Territory?

Puerto Rico is a U.S. territory, which means it is under the jurisdiction of the United States but does not have the same status as a state. It was acquired from Spain in 1898 after the Spanish-American War and has since operated as a commonwealth with a degree of self-governance. Residents of Puerto Rico are U.S. citizens, but they cannot vote in presidential elections and have limited representation in Congress.

Hawaii and Alaska are both U.S. states, having been admitted to the union in 1959. While Guam is indeed also a U.S. territory, the choice indicating Puerto Rico is still considered correct in the context of the question since it highlights one of the most well-known territories of the U.S. Both Puerto Rico and Guam have similar territorial status, but Puerto Rico is often more prominent in discussions about U.S. territories.