Assertion :- There are six different combinations or genotypes
of the human ABO blood types.
Reason :- The gene (I) has three alleles `I^(A), I^(B) and I^(0)`

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
B. If both Assertion & Reason are trur but Reason is not a correct explanation of the Assertion.
C. If Assertion is True but the Reason is Flase.
D. If both Assertion & Reason are false.

Answer

To solve the question regarding the assertion and reason related to human ABO blood types, we can break it down step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that there are six different combinations or genotypes of the human ABO blood types.
- To verify this, we need to consider the possible combinations of alleles.

2. **Identifying the Alleles**:
- The gene responsible for ABO blood types has three alleles:
- \( I^A \) (Type A)
- \( I^B \) (Type B)
- \( I^O \) (Type O)
- Each individual has two alleles, which can be any combination of these three.

3. **Listing Possible Genotypes**:
- The possible combinations of these alleles that result in different blood types are:
- \( I^A I^A \) (Blood Type A)
- \( I^A I^O \) (Blood Type A)
- \( I^B I^B \) (Blood Type B)
- \( I^B I^O \) (Blood Type B)
- \( I^A I^B \) (Blood Type AB)
- \( I^O I^O \) (Blood Type O)
- Thus, we can see that there are indeed six different genotypes.

4. **Understanding the Reason**:
- The reason states that the gene \( I \) has three alleles: \( I^A, I^B, \) and \( I^O \).
- This statement is true and directly relates to the assertion since these three alleles lead to the six different combinations.

5. **Conclusion**:
- Both the assertion and the reason are true.
- The reason provides a correct explanation for the assertion, as the presence of three alleles allows for the formation of six different genotypes.

6. **Final Answer**:
- The correct option is that both the assertion and reason are true, and the reason is the correct explanation of the assertion.