The correct answer is C. A distress alert contains information about the distressed vessel, including its name, position, and the nature of the situation, which may indicate what kind of assistance is required. This information is crucial for the Rescue Coordination Center (RCC) to mount an effective search and rescue operation. The other options are incorrect - distress alerts are not used to alert vessels about navigational hazards or weather warnings (A and D), and vessels in the vicinity of a distress situation are required to notify the RCC and render assistance if possible, rather than leave the area without notification (B).