Which source of supply (SOS) category includes all sources located outside of the medical treatment facility (MTF)?

The category that includes all sources located outside of the medical treatment facility (MTF) is the external source of supply (SOS). External sources encompass any procurement channels that are not directly part of the MTF's operational structure. This can include commercial suppliers, bulk procurement from manufacturers, and other external logistics avenues that provide medical and non-medical supplies needed to support the facility's operations and patient care.

The focus on external sources is essential as it allows MTFs to supplement their inventories efficiently, especially during periods when internal resources might be insufficient. External sourcing plays a critical role in ensuring a steady flow of necessary supplies while also enabling flexibility in procurement strategies to meet varying demands.

In this context, the other options, while related to supply sources, do not accurately represent all sources located outside the MTF as defined by the question. Internal sources refer to resources and supplies within the MTF itself. Contracted sources may include specific agreements with suppliers but are not limited to only external options, and local supply typically refers to proximate suppliers, which may not encapsulate all external sources. Thus, external is the most comprehensive category reflecting sources beyond the confines of the MTF.