Given the task definition and input, reply with output. 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.

Context: The Tansa River is a small river near Mumbai India and is one of Mumbai's water sources via Tansa Lake. It is embanked by one of the largest masonry dams in the world built in 1892. The embankment is nearly 2 miles long 118 ft (36 m) high and 30 metres thick at the base. The dam has 1.31 cubic kilometres capacity of water retention. The dam has about 38 spillway gates. This article incorporates text from a publication now in the public domain:
Question: The document can be classified to which topic?
Options: 1)Album, 2)Company, 3)OfficeHolder, 4)NaturalPlace
4