The possible father's blood groups are B, AB.
Explanation:
If the mother blood type of A, and the father blood type is AB, B then the child is B. Each biological parent donates one of their two ABO alleles to the child. The blood types in our body are classified as the four paternal blood types and the four maternal blood types.
The blood type has the 16 combinations of the blood samples. The genetic information from the body is independently inherited to the ABO blood types alleles. In the Rh factor, the genetic information is inherited from the one parent to another.