Which of the following is a common tool used for crowd control?

Fencing is a common tool used for crowd control due to its ability to create physical barriers that delineate spaces and guide crowd movement. By establishing clear boundaries, fencing helps to manage the flow of people, which is crucial during events where large numbers of attendees gather. It not only keeps the crowd organized but also enhances safety by preventing unauthorized access to restricted areas and reducing the risk of overcrowding in specific locations.

While vehicles, cones, and flags can also be utilized in various crowd management strategies, they serve different purposes. Vehicles might facilitate transportation or can be used as barricades, while cones are typically used for marking pathways or directing traffic rather than containing crowds. Flags can indicate directions or signals but lack the physical presence needed to control crowd dynamics effectively. Thus, fencing stands out as a primary tool in establishing order and safety in crowded environments.