Which form of reconnaissance involves a deliberate operation to test enemy strength?

The term "Recon in Force" refers to a specific type of reconnaissance mission where a military unit deliberately engages the enemy to assess their strength, disposition, and capabilities. This form of reconnaissance is not just about gathering intelligence passively; instead, it involves active contact with the enemy to elicit a response and gather information regarding their defenses and overall combat readiness.

By conducting a Recon in Force operation, commanders can identify strengths and weaknesses in enemy positions that may not be visible through other forms of reconnaissance, such as surveillance or observation. This method helps to paint a clearer picture of the battlefield, guiding future operational planning and tactical decisions.

In contrast, other types of reconnaissance like Area Recon or Zone Recon typically focus on surveying broader regions or specific areas without direct engagement with the enemy. Special Recon might involve unique and sophisticated methods for gathering intelligence, but it doesn't necessarily engage the enemy to test their strength in the same way that Recon in Force does. Thus, the distinctive aspect of conducting operations to deliberately test enemy strength makes Recon in Force the correct answer in this context.