Answer:
Bill's dad has blood type B
Explanation:
See punnet squares attached
It's given that the dad's blood type is homogenous -> the two letters must be the same. So we can eliminate AB, we have B and O as the options left
If the dad's blood type is O, using punnet square, we can figure out that it then would be impossible for Bill to have blood type AB (AO = blood type A) --> Incorrect
If the dad's blood type is B, using punnet square, we see that the probability that Bill has blood type AB is 100%
