When a cloned DNA fragment is used as a probe, a restriction fragment length polymorphism (RFLP) is revealed in the region adjacent to the centromere of chromosome 21. Four haplotypes exist: A, B, C, and D. An AB female and a CD male have an ACC child with trisomy 21. Nondisjunction most likely occurred during which of the following?

1. A)The child during the first mitotic division
2. B)The father during meiosis IIGABARITO
3. C)The father during meiosis I
4. D)The mother during meiosis I
5. E)The mother during meiosis II