Which of the following are key responsibilities of a Certifying Officer?

The key responsibilities of a Certifying Officer primarily center around the financial integrity and accuracy of payments made within the Department of Defense's travel system. The role involves a critical oversight function to ensure that all payments being processed are legitimate and in compliance with applicable laws and regulations. This includes verifying that transactions have adequate supporting documentation and that they align with established payment policies.

By ensuring that only valid payments are issued, the Certifying Officer acts as a safeguard against potential fraud or erroneous payments, thereby protecting the interests of the government and taxpayers. This responsibility is crucial in maintaining accountability within the financial operations of the Department of Defense, ensuring that funds are appropriately utilized and documented.

Other choices, while related to the overall management of travel claims and expenses, do not directly encompass the primary duties of a Certifying Officer. Managing system operations and tracking expenses are important elements of travel management but are not the specific responsibilities of a Certifying Officer. Submitting travel claims, while a necessary action in the travel process, falls under the duties of travelers and not the Certifying Officer. Hence, the accurate focus on the duty to ensure the validity of payments distinctly identifies the Certifying Officer's critical role in financial compliance and integrity.