What is the responsibility of the wing aircraft in a defensive sensor posture?

In a defensive sensor posture, the primary responsibility of the wing aircraft is to sanitize the route in front of the friendly force. This means that the aircraft's mission involves identifying and mitigating potential threats or obstacles that may compromise the safety and effectiveness of the unit it is supporting. By sanitizing the route, the aircraft can provide critical information to the ground forces, ensuring that they can maneuver safely and remain operationally effective. This action is vital in maintaining situational awareness and protecting the overall mission objectives, as it allows friendly forces to move through potentially hostile areas without unnecessary risk.

The other choices do not directly address the primary focus of the wing aircraft in a defensive posture. While focusing on the friendly force and concentrating on the objective are important elements of any military operation, they are secondary to the immediate need to secure and clear the airspace or ground routes that friendly forces will be using.