A Woman of Blood Group a Has a Child with a Man

A woman of blood group A has a child with a man of blood group B. The child's blood is type O. What are the genotypes of the parents?

A) Mother: I^AI^A; father: I^BI^a
B) Mother: I^Ai^O; father: I^BI^b
C) Mother: I^Ai^O; father: I^Bi^O
D) Mother: I^Ai^B; father: I^BI^O
E) It is impossible for these individuals to have a child with type O blood.