[AccessD] Help with a Select Query

Hello,
I have a client for whom I have created a simple query that returns either a home or work record if they reside within a specific district. In other words they select home or work then enter the desired district. All is well so far. The district consists of two digits 01 - 64 followed by either an 'A' or 'B'. Right now the client can request either A or B (because it's part of the district) but they would also like to be able to request both A and B. I'm really new at this and I'm wondering if there's a simple way to modify the query so they can designate either A or B or Both. The district field is three characters ##A or ##B. Each has its own district ID.
Thanks,
Cynthia