What tactical mission task involves denying the enemy access to specific areas?

The task of denying the enemy access to specific areas is best captured by the concept of "block." When forces execute a blocking mission, they aim to prevent enemy movement into or through defined terrain, effectively controlling access to key areas. This strategy is critical in defensive operations where holding ground and denying the enemy entry is essential for protecting friendly forces and objectives.

In contrast, the other options represent different tactical actions. A bypass typically refers to maneuvering around an enemy force or obstacle rather than engaging, thus it does not serve the purpose of denying access. A breach focuses on overcoming an enemy obstacle to facilitate movement for friendly forces, which again does not align with restricting enemy access. Attack by fire involves delivering effective fire against the enemy, but it does not inherently include restricting movement in designated areas. All these distinctions highlight why blocking is the correct term for the tactical mission of denying access to the enemy.