Explanation

B is correct because an iceberg floats according to Archimedes' principle, displacing a volume of water equal to the weight of the ice, and for typical sea salt density, about two-thirds remains submerged. A is incorrect as it represents too little submergence. C is incorrect as this fraction does not represent the physical reality described by buoyancy principles. D is incorrect as this fraction also does not accurately reflect the proportion required for flotation.