Parents have blood group A and B. Blood group of the child can be

Options

A. A or B
B. O
C. AB
D. All of the above

Answer

To determine the possible blood groups of a child when one parent has blood group A and the other has blood group B, we can follow these steps:

### Step 1: Identify the Genotypes of the Parents
- Blood group A can have the genotypes **IAIA** or **IAi** (where 'i' represents the O allele).
- Blood group B can have the genotypes **IBIB** or **IBi**.

### Step 2: Set Up the Possible Combinations
We will consider the combinations of the genotypes for both parents:
1. Parent 1 (Blood group A): **IAIA** x Parent 2 (Blood group B): **IBIB**
2. Parent 1 (Blood group A): **IAIA** x Parent 2 (Blood group B): **IBi**
3. Parent 1 (Blood group A): **IAi** x Parent 2 (Blood group B): **IBIB**
4. Parent 1 (Blood group A): **IAi** x Parent 2 (Blood group B): **IBi**

### Step 3: Determine the Possible Blood Groups for Each Combination
1. **IAIA x IBIB**:
- Possible offspring: **IAIB** (Blood group AB)

2. **IAIA x IBi**:
- Possible offspring: **IAIB** (Blood group AB) and **IAi** (Blood group A)

3. **IAi x IBIB**:
- Possible offspring: **IAIB** (Blood group AB) and **IBi** (Blood group B)

4. **IAi x IBi**:
- Possible offspring: **IAIB** (Blood group AB), **IAi** (Blood group A), **IBi** (Blood group B), and **ii** (Blood group O)

### Step 4: Compile All Possible Blood Groups
From the combinations above, the possible blood groups of the child can be:
- Blood group A (IAi)
- Blood group B (IBi)
- Blood group AB (IAIB)
- Blood group O (ii)

### Conclusion
Thus, the blood group of the child can be A, B, AB, or O.

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