Under 46 CFR §180.68, a vessel certificated for an oceans, coastwise, limited coastwise, or Great Lakes route must carry how many hand orange smoke distress signals?

Why C is correct

46 CFR §180.68(a)(2) requires six hand orange smoke distress signals (approval series 160.037) for vessels on oceans, coastwise, limited coastwise, or Great Lakes routes. Three is the requirement only for lakes, bays, and sounds or rivers routes per §180.68(b)(2).