Final answer:
The correct insertion methods for commandos are Airborne, submarine, and overland. These techniques have been crucial in historical military operations, such as the airborne insertions on D-Day during World War II.
Step-by-step explanation:
The three insertion methods available to commandos are A) Airborne, submarine, and overland as they represent the various ways in which elite military units can be deployed behind enemy lines or into conflict zones. For example, during World War II, airborne insertions were prominently used during D-Day, with the 82nd and 101st Airborne Divisions using parachutes to land behind enemy lines and disrupt communications. This plays a critical role in the larger strategy of military operations, whether by air, sea, or land, and each method has its own set of tactical advantages and challenges.