; (C) the owners and operators of United States-flagged vessels engaged in inland river transportation; (D) the owners and operators of United States-flagged vessels engaged in inland river transportation; (E) a nonprofit labor organization representing a class of licensed or unlicensed engine department mariners who are employed on vessels operating in the United States flag fleet; (F) a nonprofit labor organization representing a class of licensed or unlicensed mariners who are employed on vessels operating in the United States flag fleet; (G) the owners of vessels operating in the United States flag fleet, or their private contracting parties, that are primarily operating in international transportation; (H) Centers of Excellence for Maritime Training designated under section 51706 of title 46, United States Code