Shotguns are what we use in states where rifles aren't allowed. Is Alabama one of those now?
Leupold Vari-X II scope, 6x36.
The gun and scope are both top quality. The gun is in 30-30, which is the classical deer rifle caliber. Good out to 200 yds, and a bit more with the new Hornady ammo.
If you decide to get another rifle later and "downgrade" the Marlin to peep or iron sights, the scope will last pretty much forever. (Lifetime warranty too)
The scope is not too big, and not complicated. Won't ruin the lines of the gun, IMO.
Everyone is recommending bolt actions because they are a bit more accurate. For deer, that accuracy difference won't matter. Get one that is going to be easy to carry and easy to handle.