Which of the following is NOT a responsibility of an FDO?

The responsibility of an FDO, or Foreign Disclosure Officer, primarily revolves around the management and oversight of the dissemination of sensitive and classified information. This includes ensuring compliance with relevant policies and regulations, managing the release of classified materials, and coordinating with various government and military agencies to facilitate proper information sharing while maintaining national security.

Undertaking military operations overseas does not fall within the scope of an FDO's responsibilities. Their role is more administrative and advisory, focusing on the complexities of data sharing with foreign partners while adhering to established legal and policy frameworks. Thus, engaging directly in military operations is outside the functions and duties designated to an FDO, making this the correct answer.