Answer:
The genotype of the father would be [tex]I^{B}i[/tex].
Explanation:
The genotype of the mother would be [tex]I^{A}I^{B}[/tex].
The genotype of a father could be [tex]I^{B}i[/tex] or [tex]I^{B}I^{B}[/tex].
If the genotype of a father would be homozygous [tex]I^{B}I^{B}[/tex], then the blood group of offspring would be either B or AB but not A.
In contrast, if the genotype of a father would be heterozygous [tex]I^{B}i[/tex], then the blood group of the offspring would be either A, B, or AB.
Thus, the father must be heterozygous ([tex]I^{B}i[/tex]) if the blood group of the child was A.
