Which organization is responsible for providing CI functional services in support of international arms control agreements?

The Director, Defense Threat Reduction Agency (DTRA) is the correct answer because this organization is specifically tasked with implementing and supporting international arms control agreements, which often include responsibilities for verification and compliance related to those agreements. DTRA focuses on countering weapons of mass destruction and provides crucial functional services, including critical infrastructure support, to ensure that the United States meets its obligations under various arms control treaties. This includes an emphasis on cooperative threat reduction and initiatives that contribute to international security.

Other organizations mentioned serve different roles; for instance, the Joint Chiefs of Staff primarily focus on military operations and advising the President, Secretary of Defense, and National Security Council. The Department of Defense Education Activity is dedicated to providing education to children of military families and does not engage in arms control issues. The Defense Intelligence Agency focuses on intelligence support to military operations, which, while important, does not directly encompass the functional services related to international arms control agreements akin to those provided by DTRA.