The locus that controls ABO blood type in humans resides on chromosome 9. Three alleles, IA, IB, and i determine the blood type A, B, and O, respectively. The inheritance pattern of ABO blood type is illustrated in the table.

The Rh blood type is a genetic trait distinct from ABO blood type. Rh blood type is controlled by one locus on chromosome 1. The D allele determines Rh+ blood type, and the d allele determines Rh- blood type. The inheritance pattern of Rh blood type is illustrated in the table.


If the father has blood type A, Rh+ (abbreviated as A+), and the mother has blood type AB+, they have a son who has blood B-. To calculate the probability that their next child will have blood type AB+, which Punnett square is correct?