C. you can have an A or B blood type but also have recessive genes that could give an O if parent were heterozygous, like if the mother was A-i (i being recessive gene that could give 'O') and the father was B-i then if you do a punnett square then you can see that there's a 25% chance she has i-i or type O blood.
C. if the father was B, the mother was A, and the child had O, then the father had to be Bi and the mother had to be Ai
The child with type O blood can indeed have her type from biological parents with type A and B blood if both parents are heterozygous. Therefore, there is no reason for her to have concerns about her parentage. The best answer option is C: No, because both of her parents could be heterozygous.
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