Among the listed options, which maneuver type involves surrounding an enemy?

The maneuver type that involves surrounding an enemy is envelopment. In a military context, envelopment is a strategy in which forces maneuver around the flanks of an enemy position to encircle it. The primary goal of this maneuver is to cut off the enemy’s retreat and supply lines, ultimately forcing surrender or destruction of the enemy forces.

This tactic is especially effective because it can exploit weaknesses in the enemy's defenses and create situations where the enemy is caught in a crossfire or has difficulty responding to attacks from multiple directions. By engaging the enemy from the sides and rear, enveloping forces can disrupt their command and control, inflict confusion, and lead to a quick resolution of the battle in their favor.

In contrast, the other maneuver types each serve different purposes: a frontal attack aims to directly confront the enemy head-on; penetration focuses on breaking through enemy lines at a single point; and a flank attack targets the sides of an enemy formation but does not necessarily involve complete encirclement.