Answer:
C) B, secretor
D) B, Nonsecretor
E) A, secretor
F) A, nonsecretor
Explanation:
When you cross AB(codominant) with O(homozygote recessive), it will result in 50% A(IaIo) and 50% B(IaIo).
The secretor gene is dominant and both parents are a heterozygote, so the ratio of offspring genotype should be 1 : 2: 1 while the ratio of the phenotype will be 3 secretors: 1 nonsecretor.
The possible phenotype will be:
B nonsecretor
A secretor
A nonsecretor
B secretor
B nonsecretor