The ongoing process to analyze the incident and select the action to take is:

• A. Tactical operation
• B. Size-up
• C. Pre-incident plan
• D. Response phase

Answer: (B)

Size-up is the ongoing assessment of scene conditions, hazards, risks, and needs used to determine the next tactical move. It starts on arrival and continues as conditions change, guiding priorities and resource decisions. By continually evaluating factors like occupancy, fire behavior, access, exposures, and crew safety, responders decide on actions that protect life safety first and then stabilize the incident. The other options refer to different elements: a tactical operation is carrying out the chosen plan, a pre-incident plan is prepared beforehand, and the response phase is the overall period of active response rather than the ongoing analytical process. Therefore, the ongoing analysis and decision-making process described is size-up.