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 River Mellte (Welsh: Afon Mellte) is a river in Wales. It is formed by the confluence of the Afon Llia and the Afon Dringarth. It then flows south through the village of Ystradfellte to Pontneddfechan where it joins with the Nedd Fechan to become the River Neath (Welsh: Afon Nedd). The river derives its name from Mellt - the Welsh word for 'lightning' - after its tendency to rise and fall rapidly in response to heavy rainfall.
Question: The document can be classified to which topic?
Options: 1)Film, 2)NaturalPlace, 3)WrittenWork, 4)Plant
2