In this task, you are given a text which is the body of a document. You are given a question and options. Pick the correct number. Don't generate anything else apart from the numbers provided in options.
Q: Context: The Congo River (French: (le) fleuve Congo pronounced: [(l) flv k]; in the past also known as the Zaire River) is a river in Africa and the world's deepest river with measured depths in excess of 220 m (720 ft). It is the second largest river in the world by volume of water discharged. Additionally its overall length of 4700 km (2920 mi) makes it the ninth longest river.The Congo gets its name from the ancient Kingdom of Kongo which inhabited the lands at the mouth of the river.
Question: The document can be classified to which topic?
Options: 1)OfficeHolder, 2)MeanOfTransportation, 3)WrittenWork, 4)NaturalPlace, 5)Film
A:
4