Which nations in North America have only one official language?

The correct answer highlights the linguistic landscape of the nations involved in the question. The United States has English as its de facto official language, meaning it is widely spoken and used in government, though it does not have an official status at the federal level. Greenland recognizes Greenlandic as its official language, making it essentially a single-language country in terms of official recognition.

Mexico has Spanish as its official language; while it does not have any other official language at the federal level, it recognizes indigenous languages, making it not a candidate for having only one official language. Canada, on the other hand, is officially bilingual with both English and French having equal status at the federal level.

Thus, the only two nations that truly fit the criterion of having a single official language in the context given are the United States and Greenland, making the provided answer consistent with the understanding of language status in these countries.