A vessel certificated for a lakes, bays, and sounds route is required under 46 CFR §180.68 to carry a minimum of how many hand red flare distress signals?

Why B is correct

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