Which of the following is the primary frequency that is used exclusively for NAVTEX broadcasts internationally?

The primary frequency used exclusively for NAVTEX broadcasts internationally is 518 kHz. NAVTEX, or Navigational Telex, is a system designed to provide maritime information to ships concerning navigational hazards and weather forecasts. This frequency operates in the medium frequency band and is dedicated solely to NAVTEX communications, ensuring that vessels can receive timely and critical information while at sea. The use of 518 kHz allows for reliable transmission over considerable distances, which is essential for maritime safety.

While other frequencies mentioned may be used for different types of communications or localized broadcasts, only 518 kHz is designated specifically for NAVTEX globally.