Answer:
United States citizens
Explanation:
https://travel.state.gov/content/travel/en/legal/travel-legal-considerations/us-citizenship/Acquisition-US-Citizenship-Child-Born-Abroad.html
Acquisition of U.S. Citizenship by a Child Born Abroad
Birth Abroad in Wedlock to Two U.S. Citizen Parents
A person born abroad in wedlock to a U.S. citizen mother and a U.S. citizen father acquires U.S. citizenship at birth under section 301(c) of the Immigration and Nationality Act (INA), if one of the parents has had a residence in the United States or one of its outlying possessions prior to the person’s birth.