Under 46 CFR §180.68, a vessel certificated for a lakes, bays, and sounds route must carry a minimum of how many hand red flare distress signals?

Why B is correct

46 CFR §180.68(b)(1) requires three hand red flare distress signals (approval series 160.021) for vessels on a lakes, bays, and sounds or rivers route. Six are required for oceans, coastwise, limited coastwise, or Great Lakes routes per §180.68(a)(1).