What is the primary function of the Call Light Panel (CLP)?

The primary function of the Call Light Panel (CLP) is to signal the flight attendants. This panel is strategically located throughout the cabin to ensure that passengers can easily alert flight crew members when they need assistance. When a passenger presses the call button, a light illuminates on the panel, indicating to the flight attendants where they are needed. This system is crucial for maintaining effective communication between passengers and the crew, especially during service times or emergencies when immediate attention may be necessary.

The other options pertain to different functionalities in the aircraft. Controlling cabin pressure is managed through the aircraft's environmental control systems, while in-flight entertainment is typically handled by separate systems designed for media and passenger engagement. Monitoring fuel levels falls under the aircraft's operational and engineering functions, rather than passenger service aspects. Therefore, option B accurately captures the essential role of the Call Light Panel within the cabin environment.