Which of the following is an exterior sign that a building has a sprinkler system?

The presence of a Siamese connection is a clear indicator that a building is equipped with a sprinkler system. A Siamese connection is a type of fire department connection that allows firefighters to connect their hoses or apparatus to supplement the water supply for the building's sprinkler system. This configuration is typically located on the exterior of the building, making it visible and easily identifiable to first responders.

The existence of this connection signals to firefighters that the building likely has an internal network of fire suppression systems in place, which impacts tactical decisions during firefighting operations. Recognizing such signs can enhance situational awareness and fireground efficiency, allowing firefighters to focus their efforts more effectively.

Other choices such as the presence of a fire escape, heavy smoke around the building, and multiple exits provide valuable information but do not specifically correlate with the existence of a sprinkler system. Fire escapes indicate egress routes, heavy smoke may suggest a fire condition, and multiple exits relate to safety and evacuation strategies, but they do not confirm the presence of a sprinkler system.