One set of parents have death dates before Mary's birth date. Assuming the dates are reliable, that would be a good reason to choose the other pair.
12/17/2010 at 3:18 PM
I only see death dates for William Bassett (d. 1577) and Mary Roper (d. 1573). Are you able to see the death dates for the other William and Bridget Carey? They are just showing blank in the "which people are the same" box.