How often should the detection operator mark the contact to monitor if it is walking?

The correct answer is focused on the necessity of ongoing monitoring to accurately assess whether contact is walking. In dynamic situations, especially in fields such as detection operations, contact can change rapidly. Therefore, continual marking is essential to establish the movement pattern accurately.

Marking contact as many times as necessary allows the operator to make informed decisions based on the most recent data. This flexibility is crucial because a single mark may not be sufficient to capture the full scope of movement—contacts can shift positions in a matter of moments, which adds to the complexity of the situation. Frequent marking ensures that the operator has the latest information about the contact's status, which is vital for maintaining safety and operational effectiveness.

The other options suggest a limited approach to monitoring. Only marking once, a few times, or at fixed intervals like every minute does not provide the same robustness in decision-making that continuous evaluation offers. This could lead to critical gaps in awareness regarding the contact's actions, potentially affecting the success of the operation.