A father is heterozygous for type A blood and is homozygous positive for the Rh factor. A mother is heterozygous for type B blood and is homozygous positive for the Rh factor. What are the possible blood types of their offspring?
a. Type A, Type B, Type AB, Type O
b. Type A, Type B, Type O
c. Type A, Type B, Type AB
d. Type O