A Troubled Adolescent Pulled Out a Gun in a School

A troubled adolescent pulled out a gun in a school cafeteria,fatally shooting three people and injuring many others.Hundreds of parents come to the school after hearing news reports.After police arrest the shooter,which action should occur next?

A) Ask police to encircle the school campus with yellow tape to prevent parents from entering.
B) Announce over the loudspeakers, "The campus is now secure. Please return to your classrooms."
C) Require parents to pass through metal detectors and then allow them to look for their children in the school.
D) Designate zones according to the alphabet and direct students to the zones based on their surnames to facilitate reuniting them with their parents.