Which agencies operate in support roles to provide specialized support to combatant commanders and are controlled by the Secretary of Defense?

The correct choice is Combat Support Agencies. These agencies are specifically designed to provide specialized support to combatant commanders in various operational capacities. They operate under the purview of the Secretary of Defense and are integral in ensuring that the military has access to necessary resources, intelligence, logistics, and other support functions.

Combat Support Agencies are crucial for maintaining readiness and enhancing the effectiveness of military operations. They function to support the overall strategy and objectives determined by combatant commanders, facilitating coordination across different branches of the military and providing the expertise needed in complex operational environments.

In contrast, Joint Task Forces refer to temporary organizations that bring together multiple services to accomplish a specific mission or objective but do not operate in the same specialized role as Combat Support Agencies. Operations Support Commands and Strategic Air Commands, while related to various functions within the military, do not specifically align with the support structure provided by the Combat Support Agencies under the direct control of the Secretary of Defense.