You are counseling a couple with a family history of non-disjunctions. When you look at the karyotype of their fetus, you notice trisomy for one of the chromosomes, and genotyping reveals the fetus is AAa Bbb for two genes on this chromosome. Assume the genes are so tightly linked that recombination between them never occurs. The mother's genotype is Ab/ab and the father's is AB/ab. For each of the following questions mark A for True or B for False.

The fetus' genotype may have been caused by a non-disjunction event in Meiosis II in the mother O
A. True
B. False