I think that plot B might be good. Will it be in the form of first person (I, me...) if so, what pony? (Twilight, Rarity, Pinkie, Fluttershy, Applejack, Rainbow, Princess). If not, will it be in the 3rd person form, and will the character's thoughts be readable? Just some things to think about. But as I said, Plot B sounds nice.