Hmm considering Amstaffs can be dual registered as APBT isn't "pure" actually technically correct?
edit: Reading a bit more seems like it depends on if you ask the UKC or AKC. UKC considers Amstaffs to be APBT whereas AKC says the lines have been separate long enough now to be different breeds. However you can have an Amstaff registered as an APBT with the UKC and as an amstaff with the AKC.
On further thought the dog is still a purebred so "mixed" still isn't right . Sorry Erica, not trying to be nitpicky but the third is kind of a wrench thrown in making it more like a trick question