Individuals who are not U.S. citizens, or are immigrants, are not eligible for security clearances except under reciprocal clearance involving:

The correct choice, which identifies Canada and the United Kingdom, highlights the unique reciprocal arrangements these countries have with the United States concerning security clearances. Generally, non-U.S. citizens may only qualify for security clearances through agreements that allow information sharing and collaboration on defense and security matters.

Canada and the United Kingdom have established long-standing partnerships with the U.S., including intelligence-sharing alliances like Five Eyes, which enhances their eligibility for reciprocal clearances. This collaboration underlines mutual trust and the sharing of sensitive information, making it feasible for individuals from these countries to gain clearance under specific conditions.

While NATO countries as a group may have similar security interests, the specific bilateral agreements with Canada and the U.K. facilitate more direct avenues for security clearances. This is due to operational practices and historical relationships that provide these nations unique negotiation leverage with the U.S., particularly in sensitive matters of national security and intelligence operations.