Parents with the genotypes AO and AB have a child. What are all the possible blood types of the child?. Answers: which one is it.
#1 A, B
#2 O, AB
#3 A, AB, B
#4 O, AB, A

Note: the one's on the top are the given answers, the one's underneath these are hints.

Parent AO was an offspring and got his or hers gentotype from there parents allele.

Parent AB was an offspring but got his or hers from a phenotype from there parents allele.

Parent allele 1 had (A), parent allele 2 had (O). Therefore you will get offspring AO with the genotype.

Parent allele 1 had (A), parent allele 2 had (A). Therefore you will get offspring AB with the phenotype.