The U.S. Coast Guard communications station providing HF MSI broadcast coverage for NAVAREA IV is:

Correct Answer: Option B — NMF (Boston)

The USCG communications station NMF, located in Boston, is the designated authority for broadcasting Maritime Safety Information for NAVAREA IV, which covers the western North Atlantic. This station utilizes HF NBDP to ensure that vessels in this region receive critical navigational and meteorological warnings in accordance with GMDSS requirements.