my guess is no matter which answer you give them they will both point you to the same exhaust system.
It is like when you go to Autozone and you want to get a new alternator the computer will ask them if your truck is 2wd or 4x4 and if it has AC or no AC, even though all answers will lead you to the same part number for the alternator.
When it comes to exhaust for a 96 Explorer you either have a V6 or a V8.
Also there are not many exhausts "kits" for your truck, have you considered just getting a muffler and having a shop do the work?