Which reconnaissance method involves direct engagement with enemy forces?

The reconnaissance method that involves direct engagement with enemy forces is recon by fire. This approach is specifically designed to gain information about enemy positions or strength through the firing of weapons, which can provoke a response from the enemy that reveals their locations or intentions. By engaging the enemy directly, reconnaissance units aim to elicit a response that can provide valuable intelligence while also assessing the enemy's capabilities and reactions.

The other methods, while valuable in their own right, do not inherently involve direct confrontation with enemy forces. Aerial recon relies on air assets to gather information without making direct contact, whereas dismounted recon involves ground troops maneuvering to observe enemy activities but typically maintains a stealthy, non-engaging approach. Combined arms recon utilizes multiple military branches to collect intelligence, but does so through coordinated maneuvers rather than direct engagement. Thus, recon by fire stands out as the only option that explicitly includes the act of directly engaging enemy forces to gather intelligence.