There are three different alleles for blood-type: A, B, and O. A and B are dominant over O. If a person has A and B genes, he or she has blood-type AB. This is referred to as a codominant pattern of heredity.
Jane's mother and father have type B blood. When Jane's blood was tested, she found she had a blood-type of 0. Select the best response from the options below.
A. Both parents are homozygous for type B blood
B. One of them is homozygous for type B blood
C. Both parents have a recessive gene for type O blood
D. One of them has a recessive gene for type O blood