What section of U.S. Law pertains to the organization and training of the active military?

Title 10 U.S. Code is the section of U.S. law that specifically addresses the organization, training, and governance of the armed forces, including the active military. It outlines the roles, responsibilities, and structure of the Army, Navy, Air Force, Marine Corps, and Coast Guard. This title provides the legal foundation for military operations, including matters relating to enlistment, deployment, and the command structure of the active forces.

The other titles mentioned focus on different aspects of law. For instance, Title 12 pertains to banks and banking, Title 32 covers the National Guard and its operations during state and federal missions, while Title 20 is related to education and related matters. None of these titles deal directly with the active military's organization and training, which is why Title 10 is the correct choice in this context.