Two sisters are born from a father who has blue eyes and a mother who has brown eyes. One sister has blue eyes, and the other has brown eyes. Which of the following explains this difference in eye color? A Each sister inherited a different combination of alleles from their parents that determined their eye color. B One of the sisters inherited all of her alleles from the mother, and the other sister inherited only from the father. C The environment caused the alleles to be expressed in different ways, making the sisters' eye colors different. D The sister with the blue eyes had only one allele for determining eye color, and the sister with brown eyes had two.