A man with blood group A marries a woman having blood group AB. Which of the following types in the progeny of this couple would show that the man is heterozygous

Options

A. Type O
B. Type A
C. Type B
D. all of these

Explanation

To determine whether the man with blood group A is heterozygous, we need to analyze the possible blood group combinations of their offspring when he marries a woman with blood group AB.

### Step-by-Step Solution:

1. **Identify the Genotypes**:
- The man has blood group A. His genotype can either be homozygous (IA IA) or heterozygous (IA i).
- The woman has blood group AB. Her genotype is (IA IB).

2. **Gamete Formation**:
- If the man is heterozygous (IA i), he can produce two types of gametes: IA and i.
- The woman can produce two types of gametes: IA and IB.

3. **Punnett Square Setup**:
- Create a Punnett square to visualize the possible combinations of the gametes from both parents.
- The gametes from the man (IA and i) will be on one side, and the gametes from the woman (IA and IB) will be on the other side.

4. **Fill in the Punnett Square**:
- The combinations will be:
- From IA (father) and IA (mother): IA IA (Blood group A)
- From IA (father) and IB (mother): IA IB (Blood group AB)
- From i (father) and IA (mother): IA i (Blood group A)
- From i (father) and IB (mother): i IB (Blood group B)

5. **Analyze the Offspring**:
- The possible blood groups of the offspring are:
- Blood group A (from IA IA or IA i)
- Blood group AB (from IA IB)
- Blood group B (from i IB)
- If the man were homozygous (IA IA), he could only produce offspring with blood groups A and AB, but not B.

6. **Conclusion**:
- The presence of a child with blood group B indicates that the man must be heterozygous (IA i), as this is the only way to produce a child with blood group B.

### Final Answer:
The type in the progeny that would show that the man is heterozygous is **blood group B**.

---