Type A for Austin, B for Boston, and C for Chicago. Each poster will appear right next to where you click "Play Game" so you don't need to scroll down.
You want to name the city each movie used as a principal filming location. The films may not have been entirely shot in that city, but in all cases a large number of scenes were shot there. In many cases the films also took place in their given city.
In order to create a playlist on Sporcle, you need to verify the email address you used during registration. Go to your Sporcle Settings to finish the process.