Human ABO Blood Groups Are Determined by Three Alleles: IA

Multiple Choice

Human ABO blood groups are determined by three alleles: IA, IB and i. A man with blood group AB has a number of children by a woman with blood group A. Their first child has blood group B. What is the probability that the second child will also have blood group B?

A) 1/2
B) 1/4
C) 1/8
D) 1/16
E) 3/4