Option A would likely work the best for a "Dead front" appearance and is typically the cheapest/easiest to implement (but you need to carefully consider how your display bezel will get attached. Usually this piece will need to be bonded to the rest of the assembly with adhesive on the back of your masked layer.
Double Injection between clear and a dark material is possible, but requires a lot more fine tuning and you will see the area where the two pieces meet. Aside from more expensive tooling you'll see any marks that are created on the intersection between the two plastic layers. This is fine when you have two opaque materials (or the intersection his hidden) but in this case it probably hurts more than it helps.
A solid tinted material is also an option, but it will cut down dramatically on the amount of light let off the display. If you already have a display sample available, you could get some tinted sample plaques and see if they would work for your design. This is also an issue if you have screw bosses or other features built onto the bezel.