What determines whether a NAVTEX receiver prints a particular type of message content?

The correct option highlights that a NAVTEX receiver filters and processes messages based on whether they have been previously received and how the subject indicator is programmed by the operator. Specifically, a message will be printed if it hasn't been received before, which avoids duplication and unnecessary clutter of already-known information. Additionally, if the subject indicator for the message type isn't set to be rejected, the receiver will accept and print the message.

This functionality ensures that vessels only get the most relevant and new updates, helping to keep the information stream manageable and pertinent. NAVTEX receivers use a combination of serial numbers and subject indicators to streamline the information, making it essential for operators to manage these settings properly. The other options discuss scenarios where messages would either already be discarded or are prevented from being printed due to specific rejection settings, which would not align with the criteria for printing set forth in the correct answer.