Correct Response: B. As continental glaciers melted at the end of the Pleistocene epoch, vast amounts of freshwater flowed into the North Atlantic, altering the salinity of ocean water and consequently thermohaline ocean circulation. The Younger Dryas cooling event was caused by a change in northward flowing ocean currents connected to the larger thermohaline circulation of the Atlantic Ocean. The cooling of the Younger Dryas Event altered atmospheric circulation patterns and likely the position of the subtropical jet stream (A), but the Younger Dryas Event was not caused by those changes. Changes in the intensity of the solar energy output (C) were not involved in the Younger Dryas Event and although Earth's orbital parameters (D) were responsible for the major glacial cycles of the Pleistocene, they were not responsible for development of the relatively short-lived Younger Dryas Event.
