Explanation: The U.S. National Data Center is responsible for collecting Long-Range Identification and Tracking (LRIT) data from U.S.-flagged vessels. Under international SOLAS regulations, ships equipped with LRIT must automatically transmit their identity, position, and date/time at least every 6 hours. Therefore, the National Data Center **must receive at least 4 position reports daily** (24 hours / 6 hours = 4 reports) to comply with these requirements. * Option B is incorrect as hourly reports are not the standard minimum requirement for LRIT. * Option C is incorrect because "at least 1 report daily" is insufficient, and the number of crew aboard is not a standard data point for automated LRIT position reports. * Option D is incorrect because LRIT is an independent, global satellite-based tracking system primarily for governmental use, distinct from AIS (Automatic Identification System), which is a short-range, broadcast system for collision avoidance and local traffic management. LRIT is not merely a double-check on AIS.