What legislation restricts the number of Airmen serving in the top two enlisted grades?

The correct choice pertains to Title 10 United States Code, which is the specific legislation that governs the organization and management of the Armed Forces, including the number of Airmen that can hold the highest enlisted ranks. This code establishes personnel management policies, including the limitations on the rank structure, and ensures that the military maintains a balanced and effective force.

Title 10 outlines critical aspects such as the promotion selection process and the specific requirements that must be fulfilled for the highest enlisted grades, ensuring that the number of personnel in these ranks aligns with the needs of the Air Force while also considering factors such as budgetary restrictions and operational requirements. Options related to aviation regulations or national guard codes refer to different aspects of military law and do not address the promotion and rank limitations within the Air Force enlisted structure specifically. The Defense Authorization Act, while it may contain provisions affecting military operations and budget, does not directly lay out the specific restrictions on enlisted rank as Title 10 does.