Which of the following can be considered concealment?

To understand why concealment typically involves the selection of certain objects or structures, it's important to clarify what concealment means in a tactical context. Concealment refers to the use of objects to hide oneself from observation, but it does not provide physical protection from fire.

In this scenario, cover, which can effectively shield one from enemy fire, is not a proper fit for concealment since it is more about protection rather than just hiding. Open ground lacks any features that could obscure a person or object and would therefore not serve as concealment. Trees can offer concealment to some extent, as they can block the view if positioned correctly, making it a potential option. However, vehicles often provide more comprehensive concealment due to their size and structure, allowing individuals to hide behind them effectively.

Thus, while several options could be considered dependent on context, cover does not belong in the concealing category as it is inherently focused on protection rather than merely hiding from sight.