The United States has ________ states than Europe has countries; there are only 47 European countries, but there are 50 states in America.
Which of the following options correctly completes the sentence above?

Based on the context of the second clause, we know that there must be MORE states than European countries. When comparing two items, we use the comparative word, “more.” If we were comparing three or more items, we’d use the superlative form “most.”