Not a stupid thing at all to ask, but it’s not clear how to answer. As always, it will depend on what you enjoy. I’m sure you already know the classes in general. What takes your fancy?
What is PvM? Typo?
BM Hunter and either Affliction or Destro Warlock are the great soloers, ofc, with the help of heir pets.
Mage always has at least one very good spec, through all the nerfs and buffs, but you want to be ready to change spec if you want to do top performance … or you can be like me, and stick with your favourite spec even when it’s oppressed. One thing I will say for Mage is that the three specs feel very different to play, so you have quite a lot of range. It’s the weakest ranged class for soloing though, I think, and Torghast.
Balance Druid is very strong at the moment, and has all the other roles available with Druid … but you have only one ranged spec. Similarly Elemental Shaman. Basically, if the devs throw their darts and hit your one ranged spec with the supernerf dart, you don’t have another to fall back on.
Best I can recommend is to look up some YouTube videos on each and see what looks good to you.