If it says long RIFLE (or sort of...) I'm gonna say an ak, although I would grab either my AR or ak, probably dependent on which one had more loaded mags at the time. A shotgun makes probably the most sense really, even though it is rather sporting and "politically correct"...
If I had to choose, I'd take the SKS. No magazines to fuss with, all of my ammo can be immediately loadable on stripper clips, and it's more accurate than the AK-47. It also looks less like a 'black' gun in it's stock configuration if SHTF and you want to keep a low profile.