In mass casualty triage, which tag is assigned to clients who require immediate life-saving intervention?

A. Yellow tag: Indicates delayed care. These clients are stable and can wait. B. Red tag: Indicates immediate priority - patients who require life-saving interventions and have a good chance of survival if treated promptly. C. Black tag: Indicates expectant - patients are not expected to survive based on injury severity and limited resources. D. Green tag: Indicates minor injuries - patient is ambulatory and can wait for treatment.