Explanation: NAVTEX receivers are a crucial component of the Global Maritime Distress and Safety System (GMDSS), designed to provide mariners with urgent safety information. To manage the volume of incoming messages and prevent information overload while ensuring critical warnings are always received, most NAVTEX units allow operators to filter specific message categories. Option C is correct because operators can typically configure the receiver to reject less critical messages while always receiving essential navigation warnings, meteorological warnings, and Search and Rescue (SAR) information. These crucial categories (often designated A, B, and D respectively in NAVTEX transmissions) are fundamental to maritime safety and are either non-rejectable or set as default critical messages. Option A is incorrect because completely rejecting *all* categories would entirely defeat the safety purpose of the NAVTEX system. Options B and D describe non-existent operational codes or procedures for NAVTEX. There is no standard "KK" code for "ready to receive" or "00" code for "not in coastal passage." Filtering is based on message *categories* and designated broadcast areas, not these types of operational status codes.