Answer:
The blood group of Jessica can either be A or B.
In humans, the ABO blood group follows codominance in which allele
and
are codominant and allele i is recessive to other two.
The blood group of a mother is AB. Thus, the genotype of the mother would
.
Similarly, the blood group of a father is O. Thus, the genotype of the father would be ii.
The cross would result in the production of offspring with two possible types of blood groups
i and
i.
Thus, the blood group of the offspring (Jessica) can either be A or B.