One of Layman's five-step size-up process is:

• A. Preparedness
• B. Communication
• C. Probabilities
• D. Application

Answer: (C)

Assessing the likelihood of different developments is a central practice in size-up. By estimating probabilities—such as how likely it is that fire conditions will worsen, that occupants are inside, or that a structural element could fail—you tailor your actions to what is most likely to happen next. This helps you prioritize tasks, allocate resources wisely, and decide when to push interior operations versus adopting a defensive stance or calling for more help. Preparedness describes readiness before the incident, communication is ongoing information sharing, and application doesn’t fit as a deliberate step in Layman’s size-up. The probabilistic assessment directly guides immediate decisions on the scene.