what strain?

i'm doing 6 plants in my current grow, but my friend bought the seeds in canada and forgot what strain they were (ironic, to FORGET what kind of weed it is). they were bought commercially, so it's most likely a popular strain. the leaves are of moderate girth, and the rest of teh characteristics are pretty much regular indoor strain looks. but the giveaway, i hope, is that when i walk into the room it is incredibly sour. like, sour candy sour. extremely noticeable. sorry it's not much to go with, but does anyone have any idea what kind of strain this could be? thanks