My hours were reduced recently from full-time to part-time (20 hrs/wk). I applied for unemployment to cover a little of my now reduced wages. Once my paperwork was received by my employer from the Maryland Unemployment office, I was fired.

Is this legal? What are my options??

If you feel that you were fired because you filed for UI benefits, contact the state DOL again. This is a perfect wrongful termination situation, at least from the info in your post. They may handle this also, or they may advise you to contact an attorney to file your suit.