What type of educational materials does the DRM sell?

The correct answer centers around the specific focus of the DRM's offerings, which primarily involve advisory materials for DECA events. These materials are crafted to assist DECA members in preparing for competitions, enhancing their understanding of the program, and developing their skills in areas relevant to DECA initiatives.

Advisory materials are integral to helping students navigate the complexities of their events, providing them with guidance, resources, and strategies that are pivotal for success. While personal development materials, marketing-related resources, and competing materials can be beneficial in different contexts, they do not align as closely with the primary educational focus and intent of the DRM's offerings specifically tailored for DECA events. Hence, the emphasis on advisory materials distinguishes them as essential resources for participants in DECA activities.