Which tactical mission task integrates fire planning and obstacles to impede an attacker's movement?

The task that integrates fire planning and obstacles to effectively impede an attacker's movement is indeed to block. In military operations, blocking refers to the tactical mission task of establishing a position that prevents an enemy from advancing through a designated area. This involves using a combination of obstacles—such as barriers or minefields—and coordinating fire support to create a situation where the enemy's movement is significantly hindered or completely stopped.

When forces block an attack, they not only position themselves to engage the enemy but also strategically use terrain and other obstacles to create difficulties for enemy maneuvers. This task is crucial in shaping the battlefield and controlling the flow of combat, and it is designed to protect friendly forces and achieve overall mission objectives.

The other options represent different types of actions that do not specifically emphasize the integration of fire planning with obstacles for the primary purpose of impeding an enemy's advance. Seizing an objective involves taking control of it, occupying refers to holding a position, and exfiltrating pertains to withdrawing personnel from a hostile area, none of which primarily focus on impeding an attacker's movement using obstacles and firepower.