What does theater sustainment pertain to?

Theater sustainment pertains specifically to the support provided in a defined area of operations. It encompasses the logistical and operational elements necessary to maintain forces in the field, ensuring that personnel, equipment, and supplies are effectively delivered and sustained throughout the duration of military operations. This includes managing resources, coordinating supply chains, and providing necessary services to support military readiness and effectiveness in a specific theater of operations.

The other choices do not capture the comprehensive scope of theater sustainment. Supervision of military drills, while important for training, does not directly relate to the logistical and operational support in a theater. Communication protocols between units are essential for operational coordination but are not the primary focus of theater sustainment. Furthermore, the development of equipment repair plans is a part of sustainment but does not encompass the broader logistical support that theater sustainment implies. Hence, the correct choice accurately reflects the full breadth of what theater sustainment involves in a military context.