Co-dominance is seen in the person who has a blood group

Options

A. A
B. B
C. AB
D. O

Answer

To solve the question regarding co-dominance in blood groups, let's break it down step by step:

### Step 1: Understand Blood Group Genetics
Blood groups are determined by multiple alleles, specifically the alleles IA, IB, and IO. Each person inherits one allele from each parent, which determines their blood type.

### Step 2: Identify the Dominance Relationships
- IA (A allele) is dominant over IO (O allele).
- IB (B allele) is also dominant over IO (O allele).
- However, IA and IB are co-dominant to each other, meaning when both are present, they express equally.

### Step 3: Analyze the Blood Group Options
- **A Blood Group**: This occurs when the genotype is either IAIA or IAIO. Here, IA is dominant over IO, so it does not show co-dominance.
- **B Blood Group**: This occurs when the genotype is either IBIB or IBIO. Similar to A, IB is dominant over IO and does not show co-dominance.
- **AB Blood Group**: This occurs when the genotype is IAIB. In this case, both IA and IB are present and express equally, demonstrating co-dominance.
- **O Blood Group**: This occurs when the genotype is IOIO. Here, there is no co-dominance as there is only the O allele present.

### Step 4: Conclusion
Based on the analysis, the blood group that exhibits co-dominance is **AB blood group** (option C).

### Final Answer
The answer is **C. AB blood group**.

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