The purpose of "parity" in SITOR communications is?

Correct Answer: Option D — All of the above are true

Parity in SITOR refers to the constant-ratio code (4:3) used to validate data integrity. This mechanism is fundamental to both ARQ and FEC modes, as well as NAVTEX broadcasts, ensuring that any single-bit error is detected by the receiving modem, thereby maintaining the high reliability required for GMDSS.