Which type of defensive operation is designed to deny enemy access to terrain for a specific time period?

The type of defensive operation designed to deny enemy access to terrain for a specific time period is an area defense. This strategy focuses on holding and securing an area against the enemy rather than conducting a retreat or a mobile engagement. In an area defense, forces are positioned to create a defensive posture that effectively limits the enemy's movements and operations within a designated area. The primary goal is to control the terrain and prevent the enemy from gaining access, allowing your forces to maintain a stronghold.

This type of operation often includes the use of obstacles, fortified positions, and concentrated firepower to disrupt enemy advances, while also planning for potential counterattacks if necessary. By controlling the terrain, the defending forces can set the conditions for a favorable engagement or protect key assets until reinforcements arrive or conditions change.

Other options, such as perimeter defense, focus on securing the outer limits of a position or area but may not have the same emphasis on denying access over a specific time. Withdraw defense involves disengaging and maneuvering to avoid combat, while mobile defense emphasizes maintaining movement and flexibility rather than a static control of terrain.