What is the Marine Corps order for uniform regulations?

The Marine Corps order that specifically addresses uniform regulations is MCO P1020.34D. This document lays out the policies and procedures governing the wear of the Marine Corps uniform, ensuring that all personnel maintain a professional appearance that reflects the pride and standards of the Corps. It covers various aspects, including uniform components, grooming standards, and the proper way to wear insignia and decorations.

The other options pertain to different areas within Marine Corps policy. MCO 1000.1 deals with the personnel structure and management of active and reserve forces, while MCOP 1001.12 outlines provisions related to individual maritime pre-deployment training standard. MCO 5000.4A typically focuses on product support and logistics responsibilities. Thus, while they are all important orders, they do not specifically regulate uniform standards as MCO P1020.34D does.