First Choice "Lemon Juice"
But this sucked. They used fructose instead of real sugar and it tastes horrendously artificial. It certainly doesn't compare to Hot Dog on a Stick in California (gotta love the employees in those ridiculous outfits pumping up and down on that lemon-mashing shaft in the bucket).
Well, this isn't all for naught. I found a nice way to drink this crap by mixing it with soda water (in the background of the photo), thus making what the Vietnamese call soda chanh. Mmm...it actually works well.