Which two regions are considered the least populated in North America?

The correct choice identifies Canada and Greenland as the least populated regions in North America. Canada, despite its vast size, has a relatively low population density, mainly due to its large expanse of uninhabitable land, including mountains and forests. Similarly, Greenland has a very small population primarily concentrated along its coasts, with the interior being largely uninhabitable due to its ice cover.

While the other options include regions that have larger populations, such as Mexico and the USA, they do not accurately represent the least populated areas. Mexico has a significant population, making it one of the most populous countries in North America. The USA also has a large and diverse population spread across its various states. Therefore, the choice highlighting Canada and Greenland is accurate, as both regions are characterized by vast, sparsely populated territories.