Polydactyly (extra digits) is a dominant trait caused by gene P, as opposed to the normal allele p. Cystic fibrosis, f, is a recessive disease, as opposed to the normal condition, F. A polydactylous woman, otherwise normal in phenotype, has kids with a healthy normal man. Their 4 children have the following phenotypes:

Child 1 is phenotypically normal in all respects
Child 2 is polydactylous, otherwise phenotypically normal
Child 3 has cystic fibrosis, otherwise phenotypically normal
Child 4 has cystic fibrosis and is polydactylous

What is the probability that their 5th child will have cystic fibrosis and be polydactylous?

a. 1/4 (0.25)
b. 1/2 (0.5)
c. 1/8 (0.125)
d. 3/8 (0.375)
e. 3/4 (0.75)