The correct answer would be "A". Both parents have curly hair. Which means that they both have a least one dominant C. However, only two of the three children have curly hair. For the one that doesn't, she would have had the recessive trait. So one of the parents has to have one dominant and one recessive. One parent has to be dominant because with that, there is a 75% chance that the child would have curly hair. The correct answer is "A".