Step 1: Triage is the rapid classification of injured people in a mass emergency according to the severity of injury and likelihood of survival with prompt care, so the usual first come first treated rule is not followed.
Step 2: The most common international system is a four-colour code: Red for high-priority treatment or transfer, Yellow for medium priority, Green for ambulatory patients, and Black for the dead or moribund.
Step 3: Green therefore denotes ambulatory (walking) patients with minor injuries who can wait, making ambulatory the correct answer.
Step 4: High priority corresponds to Red and the lowest priority (moribund) to Black, so options other than ambulatory do not match the green tag.