Explanation: NAVTEX receivers are designed with sophisticated filtering capabilities to manage the volume of incoming messages. Users can program the receiver to reject broadcasts from specific transmitting stations (identified by their unique B1 character). Additionally, unwanted message categories (identified by their B2 character, e.g., navigational warnings, meteorological forecasts, search and rescue information, or test messages) can be deselected, preventing their reception and display. This allows operators to customize the information received to their specific needs and geographic area. Options B, C, and D are incorrect. NAVTEX operates continuously, 24/7, on frequencies (like 518 kHz) that are not limited to daytime operation; in fact, MF signals often have increased range at night due to skywave propagation. While broadcast schedules exist, coordinating with them only informs when broadcasts occur, it doesn't prevent reception of unwanted messages. Automatic receiver desensitization is not a standard feature for filtering NAVTEX and would generally be an undesirable reduction in sensitivity, not a user-controlled method to prevent specific broadcasts.