Final answer:
The investigation of an unknown device on a company's internal network and implementing preventative measures align with the responsibilities of the Security Operations domain.
Step-by-step explanation:
The scenario you described relates to the Security Operations domain. This domain deals with the activities and decisions made to protect a company's information assets through handling alerts, incident response, and implementation of preventative measures. Investigating an alert about an unknown device on the company's internal network and then applying preventative measures to mitigate any potential threat is a classic responsibility of the security operations team. They are charged with the ongoing management of security procedures within the company's network, which includes continuously monitoring security systems and responding to security incidents to ensure the safety and integrity of company data.