A vessel on an oceans, coastwise, limited coastwise, or Great Lakes route is required by 46 CFR §180.68 to carry how many hand red flare distress signals?

Why B is correct

46 CFR §180.68(a)(1) requires six hand red flare distress signals (approval series 160.021 or 160.121) for vessels on oceans, coastwise, limited coastwise, or Great Lakes routes. Three hand flares are required only for lakes, bays, and sounds, or rivers routes under §180.68(b)(1).