Not sure which one of B, C or D is correct....    A...Deck line parallel to water line...Ok, thats easy. Just a square.   In cases B, C and D, the deck line not parallel to W.L.    B is like A....the left and right sides vertical to the Water Line, up and down parallel to the W.L.  C has left and right sides vertical to the Water Line, up and down parallel to the Deck....Not a square. No right angles.  D is a square with left and right sides "vertical" to the Deck Line, up and down "para