Which of the following describes a reasonable concern for a person's safety?

A recent check-in failure or missed communication is a reasonable concern for a person's safety because it can indicate that something has gone wrong. Regular communication is essential for ensuring that individuals, particularly those who may be vulnerable, are safe and accounted for. When someone fails to check in or communicate as expected, it raises red flags that require immediate attention, as it may signal that the person is in danger or experiencing distress.

In contrast, unusual behavior reported by peers might be concerning but could also be subjective or context-dependent; therefore, it may not directly indicate a safety risk. A history of school difficulties can highlight past challenges but doesn’t necessarily correlate with an immediate safety issue. Lastly, while statements made on social media can reflect a person's mental state or concerns, they may not always serve as a clear indicator of immediate safety risks without further context. Thus, the missed communication stands out as a direct and actionable concern for safety.