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 Gemini Center is a complex comprising two skyscrapers located in Milan Italy at the most peripheral end of Via Lorenteggio in the Giambellino-Lorenteggio district adjacent to Milan's border with Corsico. The two towers are 96 m 21 stores high; they were designed by architects R. Gantes and R. Morisi.A distinctive trait of the Gemini Center towers are two cranes located on the buildings' top which are used for cleaning the glass panes that cover most of the towers' external surface.
Question: The document can be classified to which topic?
Options: 1)Artist, 2)WrittenWork, 3)MeanOfTransportation, 4)NaturalPlace, 5)Building
5