The more sunlight our planet reflects back into space, the cooler the global atmosphere tends to become. Snow and ice reflect much more sunlight back into space than do ocean water or land without snow cover. Ttherefore, the greater the area of Earth' s surface that is covered with snow and ice, the cooler, on average, the global atmosphere is likely to become. Which one of the following, if true, would most strengthen the argument? ["Other factors besides the reflectivity of ice and snow affect the cooling of Earth's atmosphere.", 'The atmosphere derives most of its heat from the passage of sunlight through it.', 'Lighter-colored soil reflects more sunlight back into space than does darker-colored soil.', "Ocean water and land heated by sunlight in turn warm Earth's atmosphere."]