D) Somewhere on the back of the refrigerator, usually very high or very low, or possibly on any wiring diagram that may be pasted to the back of the refrigerator.
E) If you absolutely cannot find a metal nameplate, some refrigerators have a paper sales sticker left on, just inside the door. This will be an incomplete model number, but it is better than nothing and it should be good enough to get most parts with.
If all else fails, check the original papers that came with your fridge when it was new. They should contain the model number SOMEWHERE.