Blood Group Probability Analysis

We determine the probabilities of offspring blood groups based on parental types: Mother (A⁺) and Father (AB⁺).

ABO Blood Group Probabilities

The Father's ABO genotype is definitively $A^i B^i$. The Mother's phenotype is A. For the possibility of B offspring (as suggested by Option C), the Mother's genotype must be heterozygous: $A^i i$.

Cross: Mother ($A^i i$) $\times$ Father ($A^i B^i$).

This cross yields the following ABO phenotype probabilities:

• P(A) = P($A^i A^i$) + P($A^i i$) = 1/4 + 1/4 = 0.5
• P(B) = P($B^i i$) = 1/4 = 0.25
• P(AB) = P($A^i B^i$) = 1/4 = 0.25
• P(O) = 0

Rh Factor Probabilities and Combined Analysis

Both parents are Rh positive (A⁺, AB⁺). Let R represent the Rh⁺ allele and r represent the Rh⁻ allele. Rh⁺ is dominant.

Analysis of Statement A: P(A⁺) = 0.5

This probability requires P(A) $\times$ P(Rh⁺) = 0.5.

Given P(A) = 0.5, this necessitates P(Rh⁺) = 1. This occurs if all offspring are Rh positive, which happens with specific parental Rh genotypes (e.g., Mother $A^i i RR$ and Father $A^i B^i Rr$).

Under these assumptions, P(A⁺) = 0.5 $\times$ 1 = 0.5.

Thus, Statement A is considered correct.

Analysis of Statement C: P(B⁺) = 0.125

This probability requires P(B) $\times$ P(Rh⁺) = 0.125.

Using P(B) = 0.25, we find P(Rh⁺) = 0.125 / 0.25 = 0.5.

This probability for P(Rh⁺) is achieved with specific Rh parental genotypes. Under these conditions, P(B⁺) = 0.25 $\times$ 0.5 = 0.125.

Thus, Statement C is considered correct.

Summary of Correct Statements

Based on the genetic analysis and the assumptions required to match the probabilities:

• Statement A is correct.
• Statement C is correct.