Administrative Controls: These are the policies, procedures, guidelines, and standards that define the overall security management of an organization. They focus on the "human" aspects of security, such as training, awareness, and policy enforcement. Mandating cybersecurity awareness training falls squarely within this category. It's a management decision implemented through a policy.
Why the other options are incorrect:
Technical Controls: These involve the use of technology to enforce security. Examples include firewalls, intrusion detection systems, antivirus software, and encryption. While technology might be used to deliver the training (e.g., an online course), the training itself is not a technical control.
Operational Controls: These are the day-to-day activities and procedures carried out by individuals to maintain security. They often involve a combination of administrative and technical controls in action. While the execution of the training program could be considered operational, the policy mandating it is administrative.
Preventive Controls: These are designed to prevent security incidents from occurring in the first place. While cybersecurity awareness training aims to prevent incidents by educating users, the training itself is an administrative measure. Many types of controls can have a preventive effect (e.g. a firewall is a technical preventive control). The key here is that the question asks for the type of control the training is, not its effect.