What is required when CTF-70 is embarked and returning?

When CTF-70 is embarked and returning, a stinger is required. This requirement is in place for operational security and safety when a task force or an operational group such as CTF-70 is in proximity. The stinger is essentially a small boat or other quick response vessel that provides immediate alert capabilities, enhancing the ship's defensive posture against potential threats.

This requirement underscores the importance of readiness and vigilance during critical maneuvers when high-profile units are involved. The presence of a stinger ensures that there is a rapid response to any unforeseen incidents, promoting a secure and safe environment for the personnel on board and the mission being conducted.

The other options, while they may seem plausible, do not address the specific operational requirements associated with CTF-70’s involvement. Additional crew on watch or advanced security clearance may be necessary in different contexts but are not explicitly required for the scenario described. Thus, the requirement for a stinger reflects the need for enhanced security and immediate response capabilities.