ABO blood grouping is controlled by gene I, which has three alleles: .

1. Male (Group A): Genotype can be or .
2. Female (Group B): Genotype can be or .
3. Progeny: The question states progeny are either Group AB () or Group B ().
4. Analysis:

• For offspring to be Group B ( or ), the male must contribute an 'i' allele (since he is Group A, he cannot contribute ). Thus, the male must be heterozygous ().
• For offspring to include Group AB (), the female must contribute and the male .
• If the female were heterozygous (), the cross would produce offspring with Group A () and Group O () as well . Since only AB and B are observed, the female must be homozygous dominant ().
• Cross: Male () Female () Progeny: (AB) and (B).