Answer:The best fit for the blank is A. coast.Here's why: * A. coast: A coast is the part of the land adjoining or bordering the sea, ocean, or a lake. Ships typically seek passages along coasts. * B. inland: Inland means away from the coast or a border; in the interior of a country or region. Ships don't seek passages inland. * C. body of land with water on three sides: This describes a peninsula. While ships might sail around a peninsula, "passage along a southern peninsula" is a bit clunky and less direct than "along a southern coast" if they are simply following the shoreline. * D. border: A border is a line separating two countries or political units. While some borders might follow coastlines, "passage along a southern border" isn't the primary way to describe a ship's route in relation to land.Therefore, "Four of the ships sought a passage along a southern coast" is the most natural and accurate phrasing.