A person who is under age 21 and for whom there is reasonable concern for their safety falls under which classification?

The classification of "Juvenile EMJ" is appropriate for a person who is under age 21 and for whom there is reasonable concern for their safety because it specifically addresses individuals who are minors or young adults under a certain age, typically recognized as being vulnerable. This classification ensures that this age group receives the special attention and resources they may need due to their age and the potential risks associated with their safety and well-being.

In the context of NCIC classifications, juveniles are often at higher risk and might be more susceptible to various threats or dangers, thus warranting a distinct classification that focuses on their specific needs in situations involving safety concerns. This focus on juveniles emphasizes both the protection and proactive measures taken in law enforcement and support services.

The other classifications may pertain to different demographics or situations, such as specific disabilities or catastrophic incidents, but none of them address the unique considerations necessary for minors or young adults in terms of safety and protection under the law. Therefore, "Juvenile EMJ" is the most fitting classification in this case.