Identify which of the following regions are in South America: Argentina, Brazil, China, Mexico.
Argentina and Brazil are regions in South America, while China and Mexico are not. China is in Asia, and Mexico is in North America.
Complete the following task based on the instruction and optional input provided.### Instruction:
Identify which of the following regions are in South America: Argentina, Brazil, China, Mexico.

### Output:
Argentina and Brazil are regions in South America, while China and Mexico are not. China is in Asia, and Mexico is in North America.