Attached ear lobes (allele A) is dominant to unattached lobes (allele a). John and Sally have attached ear...?

lobes, but each of them have one parent with unattached ear lobes. John and Sally have 4 children now. How many of their children would you expect to have unattached ear lobes? A. 1 B. 0 C. 3 D. 2 E. 4