What defines a missing child?

A missing child is specifically defined as an individual who is 17 years old or younger. This classification is crucial in the context of law enforcement and child protection, as it sets the parameters for response and intervention. When determining whether a child is considered missing, age plays a vital role since children under this age are often perceived as being unable to make safe choices or fully comprehend their circumstances.

The other options do not fit the legal and operational definition of a missing child. For instance, a child aged 18 or older is considered an adult and thus falls outside the scope of missing children cases. While situations in which a child is lost at a public event or runs away from home can indeed result in a child being classified as missing, these scenarios are subsets of the broader definition that emphasizes age. Therefore, the proper context to understand "missing child" primarily hinges on the age limitation of 17 years or younger.