Well, it obviously isn't Terrell Pryor. He might have not lived up to the hype, but he has 2-1 in BCS bowl games in 3 years, with 2 BCS bowl game MVPs and a career record somewhere near 33-5. He also has a career rating over 120.
My guess is it's someone who's father was famous and only got on the team as a 5th stringer at a d3 school.
if they were so bad, obviously they wouldnt be starting would they. plus there are 120 d1 schools lone. there are over 3000 colleges in the usa. there are probably thousands of schools with programs. and most of the schools have around 3 to 4 qbs. so youre asking a person to pick the worst qb out of probably over 4000.