cellphones – Is it possible to buy a SIM card in a transit zone of Doha airport?

The Doha Airport’s official webpage contains a link to a page of maps of the various terminals and concourses.

The maps for Transit Concourses A, B, D, and E show various facilities (seating, restrooms, customs/immigration desks, etc.) but do not show any shops or stores in these areas.

There is no map for a Transit Concourse C, which may or may not exist. I’ve never been this airport.