How to create a drop down field to categorize content when creating new pages? I want to have a drop down field available so that when a content author (user) creates a new page, they can select which section of the website this new content should get placed.

For example, my top navigation may be About Us > Services > Products. A user creates a new page that should go on in the Products section. When they go to add the new page, there should be a drop down field that shows About Us, Services, Products. The user would select Products and when they save the page, that page will automatically get placed in the Products section of the website. 

Can anyone tell me how to achieve this?
The drop-down can be created as a Taxonomy.

The section pages can all be one View with a Contextual Filter for each taxonomy term.