I'll vote for D. BUT you get an A+ for finding such a variety of shells. St. Barths these days does not have a great variety -- or number of any shells.
i have almost every single one of those shells, ricky. however, i got f from a beach in wilmington, north carolina. the one i do not have is c...i think....maybe if you flipped it over, i could better tell. so, with the information i have, i'm going with C....my final answer!