Which role is held by Cadet Lieutenant Junior Grade Layla Greenleaf?

Cadet Lieutenant Junior Grade Layla Greenleaf serves as the MAST Battalion Community Affairs Officer. In this role, she is responsible for managing the interactions and initiatives between the battalion and the community. This position typically involves organizing events, promoting the battalion's image, and fostering positive relationships with local organizations and the public. Community Affairs Officers play a crucial part in outreach and public engagement, which can enhance the battalion's presence and impact within the community.

The other roles listed, such as Supply Officer, Chief, and Training Officer, have distinct responsibilities focused on logistics, leadership within a company, and training oversight, respectively. While each role is integral to the operation of a battalion, the Community Affairs Officer specifically targets external relations, making it the correct answer for the question.