Final answer:
An individual with blood type O can be the child of parents with blood types A and B if both parents carry the recessive 'i' allele. The most likely parents of the O-type infant are those where each parent contributes an 'i' allele.
Step-by-step explanation:
The question relates to genetics and blood type inheritance. An individual with blood type O (genotype ii) can indeed be the legitimate child of parents where one parent has blood type A (possible genotypes AA or Ai) and the other parent has blood type B (possible genotypes BB or Bi). This is because the O blood type allele is recessive, requiring two copies for the O blood type to be expressed (ii). Thus, if each parent provides an 'i' allele, the child can have blood type O.
For the infant with O blood type being claimed by 5 sets of parents at the Tampa hospital, the most probable biological parents would be the ones where one parent could have genotype Ai (blood type A) and the other parent could have genotype Bi (blood type B), with both parents having contributed the recessive 'i' allele to the infant.