What tactical mission task ensures a terrain feature remains free of enemy use?

The correct choice, which is to retain, refers to a tactical mission task that focuses on maintaining control over a specific terrain feature to prevent enemy forces from utilizing it. This task is crucial in military operations, as it involves not only holding the ground but also denying access to adversaries, thereby ensuring that the area remains under friendly control and can be used to the advantage of friendly forces.

When a unit is assigned the mission to retain an area, they continuously monitor and defend that terrain, securing it from enemy infiltration or occupation. This may involve fortifying positions, conducting patrols, and engaging any enemy forces attempting to approach the terrain. Retaining a feature is often necessary for maintaining supply lines, protecting flanks, or supporting overall operational goals.

The other choices involve different tactical mission tasks that, while related, do not specifically convey the act of ensuring that an area remains free from enemy use in the same way. Guarding refers to securing an area while also covering a specific unit or position, fixing typically means to engage and hold an enemy in place, and interdiction focuses on preventing enemy movement or supply before they reach a designated area, rather than securing a feature itself.