The correct answer is option 2: Santos. Santos is known as the "Coffee Port" of the world.

Option 1: Sao Paulo is a city in Brazil, but it is not specifically known as the "Coffee Port" of the world.

Option 3: Rio de Janeiro is another city in Brazil, but it is not known as the "Coffee Port" of the world.

Option 4: Buenos Aires is the capital city of Argentina and is not known as the "Coffee Port" of the world.

Santos, on the other hand, is a coastal city located in the state of Sao Paulo, Brazil. It has a major port that is famous for exporting coffee. Brazil is one of the largest producers and exporters of coffee in the world, and Santos` port plays a significant role in this industry. The city has a long history of coffee production and trade, and therefore, it is widely recognized as the "Coffee Port" of the world.