A man having blood group O marries a woman having blood group A. What are the probable phenotypes of the offspring?

The genotype of the man is ii

The genotype of the woman can be ${\mathrm{I}}^{\mathrm{A}}{\mathrm{I}}^{\mathrm{A}}$ or ${\mathrm{I}}^{\mathrm{A}}\mathrm{i}$

If the genotype of the woman is ${\mathrm{I}}^{\mathrm{A}}{\mathrm{I}}^{\mathrm{A}}$, then

${\mathrm{I}}^{\mathrm{A}}{\mathrm{I}}^{\mathrm{A}}$x ii

All offspring would have genotype ${\mathrm{I}}^{\mathrm{A}}\mathrm{i}$. Therefore, all offspring would have blood group A.

If the genotype of the woman is ${\mathrm{I}}^{\mathrm{A}}\mathrm{i}$, then

${\mathrm{I}}^{\mathrm{A}}\mathrm{i}$x ii

Offspring would have genotype ${\mathrm{I}}^{\mathrm{A}}\mathrm{i}$or ii.

Therefore, the blood group of the offspring would be either A or O.