The correct answer is option 1: USA. Lake Superior, the largest freshwater lake in the world, is shared by the United States and Canada. However, the lake is mainly situated in the United States. It is one of the five Great Lakes of North America and is located predominantly in the state of Michigan. The lake`s vast size and strategic location contribute to its significance as an important waterway for shipping and transportation.

Option 2, Brazil, is incorrect. Lake Superior is not located in Brazil. Brazil is a country in South America and does not have any of the Great Lakes within its borders.

Option 3, Canada, is partially correct. While a portion of Lake Superior is located in Canada, the majority of the lake is situated in the United States.

Option 4, Russia, is incorrect. Lake Superior is not located in Russia. Russia is a country in northern Eurasia, far from the Great Lakes region of North America.

In summary, Lake Superior is primarily located in the United States, making option 1 the correct answer.