I would go with Cook if he's available in the second round or Prescott or Hackenberg whichever is available in the third round.
Positives for Cook: Long time starter, good accuracy, good size and arm strenght. Negatives: Got hurt a bit. Leadership questions which may or may not be unfounded.
Positives for Prescott: Good size, arm strenght, winner and played vs very tough defenses in college. Negatives: A bit raw, needs developing.
Positives for Hackenberg: Good size and arm strenght. Played in a pro style offense. Has all the physical tools. Negatives appeared to have regressed his last two years. Needs time to develop and correct flaws.