The Sargasso Sea (note: spelled 'Sargasso', not 'Saragossa' in the option, but this is clearly referring to it) is the only sea without a coastline. It's defined by ocean currents in the North Atlantic Ocean, bounded by the Gulf Stream, North Atlantic Current, and other currents. All other seas listed (White Sea, Sea of Okhotsk, Tasman Sea) are marginal seas with coastlines.