What is Marine Corps I primarily used for?

The primary use of Marine Corps I is for presidential flights, specifically to transport the President of the United States. Marine Corps I is a designation for the aircraft used to ensure the president can travel securely and efficiently. It provides the necessary communication and security infrastructure and is staffed by Marine Corps personnel trained to handle the specific requirements of presidential travel. The aircraft plays a critical role in executing the responsibilities of the office while maintaining the safety and operational capabilities required for such high-profile missions.

While the other options involve important aspects of military operations, they are not the defining role of Marine Corps I. For instance, transporting injured Marines relates to medical evacuation missions, training exercises are aimed at preparing personnel for various scenarios, and transporting military personnel encompasses a broader scope of military logistics. However, none of these embody the specific function of Marine Corps I in the context of presidential transport.