It depends on what she's gonna be using the light for, really. The Malkoff MD2 is always a good choice, but is gonna require a belt holster and takes CR123 batteries. Being that's she's going to be working in a jail/prison, there really shouldn't be a time that she's in an unlit area and needing a lot of light unless she's patrolling the grounds around the perimeter of the place, and even then she'll most likely have a vehicle or at least a big issued flashlight.
For every day carry & use (checking cells for contraband, etc.), I'd say she'd be better off with one of the AA LED lights with a pocket clip - a Streamlight ProTac 2AA would fit in the pen flap of a uniform shirt, goes from very bright 150+ lumens to night time "see your way down a dimly lit corridor" 11 lumens, and use batteries that are much cheaper than CR123s.