Which Army regulation primarily addresses uniform regulations?

The choice of AR 670-1 as the correct answer is based on its specific focus on apparel standards within the Army. This regulation outlines the policies and procedures concerning the wear of the Army uniform, including guidelines related to appearance, insignia, and other uniform components. It is comprehensive, detailing the standards expected of Soldiers in maintaining discipline and professional appearance in accordance with Army values.

In contrast, AR 600-20 addresses Army command policy, which encompasses a broader range of topics including the implementation of leadership and unit policies. While command policy is vital for the overall functioning of military units, it does not primarily focus on uniform regulations.

ADP 1-0 centers on the Army's organization and command structure, detailing the roles and responsibilities within the Army. Similarly, ADP 6-22 covers Army leadership and the competencies required for effective leadership. These documents are critical for understanding the Army's operational effectiveness and leadership principles but do not directly address uniform policies.

Therefore, AR 670-1 is distinctly recognized for its exclusive and comprehensive approach to uniform regulations, making it the correct answer in this context.