Final answer:
The Air Force Installation and Mission Support Center (AFIMSC) verifies WRM ration requirements and issues the Rations Authorization Letter to MAJCOM/bases.
Step-by-step explanation:
The entity responsible for validating WRM ration requirements and sending the official Rations Authorization Letter to the Major Command (MAJCOM)/bases is typically the Air Force Installation and Mission Support Center (AFIMSC). This center operates under the United States Air Force and is tasked with ensuring that War Reserve Materiel (WRM) needs are met efficiently and in accordance with strategic objectives. Once the requirements are validated, the AFIMSC issues the Rations Authorization Letter to the relevant MAJCOM/bases to authorize the necessary support for operations.