Out of the given choices, the country which is not in South America is letter D or Mexico. Mexico, or officially known as the United Mexican States, is in the southern part of North America. It is ranked 13th in terms of area which covers a total area of 1,972,550 square kilometers. In terms of population, the country is ranked 11th with a total population of more than 123 million people.
Brazil, Chile and Argentina are all in South America. Brazil is ranked 5th and 6th in terms of area and population respectively, Chile is ranked 37th and 65th in terms of area and population respectively and Argentina is ranked 8th and 31st in terms of area and population respectively.