Which measure would be considered a form of primary prevention for suicide?

A. Referral of a formerly suicidal patient to a support group is a form of tertiary prevention, aimed at preventing recurrence and promoting recovery after an event. B. Psychiatric hospitalization of a suicidal patient is considered secondary prevention, targeting individuals at immediate risk to prevent harm. C. Suicide precautions for 24 hours for newly admitted patients is secondary prevention, focused on intervening during a high-risk period. D. Helping school children learn to manage stress and be resilient is primary prevention, aimed at preventing the onset of suicidal behaviors before any signs or risk factors appear.