Answer:
A
AB
Step-by-step explanation:
This question involves blood type, which can either be blood type A, B, AB or O in humans. Alleles A (iA) and B (iB) are co-dominant but dominant over allele O (i).
According to this question, a mom who is heterozygous for type B blood i.e. genotype iBi, has a baby with type AB blood. Since the mother contributed the "B" allele, it means that the father contributed the A allele. Only a father with genotype: iAi or iAiA (type A) or iAiB (type AB) can produce such allele.