AIIMS 2019 Zoology Blood Groups MCQ Question

When the father's blood group is A (genotype can be AA or AO) and the mother's blood group is B (genotype can be BB or BO), the possible combinations of alleles from the parents can produce progeny with blood groups A, B, AB, or O. Specifically, the combinations can yield genotypes AA, AO (resulting in blood group A), BB, BO (resulting in blood group B), AB (resulting in blood group AB), and OO (resulting in blood group O). Therefore, option D is correct as it includes O, A, and B, which are all possible blood groups of the progeny.

Option A is incorrect because it omits blood group O, while option B includes it but inaccurately suggests that O is a guaranteed outcome. Option C is also incorrect as it excludes blood group O, which can occur if both parents carry the O allele.