What is an example of a reasonable ground for suspicion?

A reasonable ground for suspicion is based on observable behavior or evidence that indicates potential criminal activity. When a person is acting suspiciously in an area known for crime, it provides law enforcement or park wardens with concrete observations that warrant further investigation. This context emphasizes a connection between the person's behavior and the crime-laden environment, allowing for a justified suspicion that something may be amiss.

The other options lack this direct association with observable and indicative behavior linked to criminal activity. For instance, simply seeing someone run does not inherently suggest suspicious behavior; it could be entirely innocuous. Hearing loud noises can also occur for a variety of reasons that do not necessarily indicate wrongdoing. Lastly, while an anonymous tip can be a source of information, it often lacks the immediate contextual evidence that a specific person's behavior in a known crime area provides. This is why option C stands out as the strongest example of reasonable ground for suspicion.