How can people become United States citizens?

What does this answer mean?

There are three ways people become U.S. citizens, and you only need to name one. USCIS accepts: being born in the United States under the conditions set by the 14th Amendment, naturalizing, or deriving citizenship under conditions set by Congress.

Birth in the United States comes from the 14th Amendment, ratified in 1868. It says all persons born or naturalized in the United States, and subject to its jurisdiction, are citizens of the United States and of the state where they live.

Naturalization is the process this site is about: a lawful permanent resident who meets the requirements Congress has set, such as the residence, English, and civics requirements, applies and becomes a citizen.

Citizenship through parents is the third way. USCIS explains that a person can acquire citizenship through U.S. citizen parents, either at birth or after birth but before turning 18. The exact conditions are set by law and depend on the facts of each case.

At the interview, the answer most applicants know best is "naturalize."