I might be wrong but as the options for FINAL professions I would say:
Alch - 300 Classic, maybe TBC?, 75 Northrend
Engineering - 300 Classic, 75 Northrend, 75 Cata, 25 or 40 Pandaria(?), 1 WoD
Jewelcrafting - 300 Classic(?), 75 TBC(?), 75 Northrend
Anyways it really depends on whether you're...