Topic: Article,

Best Answer Explained in Below-:

The correct answer to the sentence "We visited __." is C) "Canada and the United States" for several reasons related to grammatical correctness and conventional usage in English.

First, option C presents the countries without the definite article "the," which is the standard form used when referring to Canada and the United States in simple declarative sentences. Both "Canada" and "the United States" are proper nouns, and when listing two countries, particularly in a non-complex manner, it’s common to omit articles for clarity and brevity.

Option A) "Canada and United States," while it may seem plausible, lacks the definite article before "United States," which is grammatically incorrect and sounds awkward to native speakers. Each country is named correctly, but the omission of "the" before "United States" breaks the flow and conformity of standard English structures.

Options B) "The Canada and the United States" and D) "The Canada and United States" include the article "the" before "Canada." However, "Canada" does not require "the," making these options incorrect.

Thus, option C is the only grammatically sound choice and perfectly conveys the intended meaning without awkwardness or redundancy.