Which act authorized the president to imprison or deport non-citizens deemed dangerous?

The correct choice is the Alien Enemies Act. This act, passed in 1798, specifically allowed the president to imprison or deport non-citizen residents who were citizens of countries with which the United States was at war or considered hostile. The law was part of a larger set of acts known as the Alien and Sedition Acts, which aimed to restrict the activities of foreign nationals within the U.S. during a time of heightened political tension.

The other options present laws that are not related to the president's authority regarding non-citizens. The Naturalization Act primarily focused on the process by which immigrants could become citizens. The Homestead Act was concerned with providing land to individuals in the United States, particularly to encourage westward expansion. The Alien Friends Act also permitted the president to expel non-citizens deemed dangerous, but it did not specifically address the same level of authority or context as the Alien Enemies Act concerning those from enemy nations.

Overall, the Alien Enemies Act is the specific legislative framework established to address concerns about foreign nationals who could pose a threat during times of conflict.