A : Blood group phenotype is controlled by presence or absence of antigens present on surface coating of RBC.
R : These antigens are of three types and four in the oligosaccharides rich head regions on glycophorin.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true and the reason is not the correct explanation of the assertion , then mark (2)
C. If Assertion is true statement but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To solve the assertion and reason question regarding blood group phenotypes and antigens, we will break down the information provided in both the assertion (A) and the reason (R) statements step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that the blood group phenotype is controlled by the presence or absence of antigens on the surface of red blood cells (RBCs).
- Blood groups are classified into four types: A, B, AB, and O, based on the specific antigens present.

2. **Identifying Antigens**:
- In individuals with blood group A, A antigens are present on the RBCs.
- In individuals with blood group B, B antigens are present.
- Individuals with blood group AB have both A and B antigens.
- Individuals with blood group O have no antigens on their RBCs.

3. **Understanding the Reason (R)**:
- The reason states that there are three types of antigens and four in the oligosaccharides rich head regions on glycophorin.
- However, the primary antigens relevant to blood groups are A and B. The statement about three types of antigens is incorrect as it overlooks the fact that O blood group does not have any antigens.

4. **Evaluating the Truth of A and R**:
- The assertion (A) is true because blood group phenotypes are indeed determined by the presence or absence of specific antigens.
- The reason (R) is false because it incorrectly states that there are three types of antigens when there are actually only two types (A and B).

5. **Conclusion**:
- Since the assertion is true and the reason is false, we can conclude that the correct answer to the question is that the assertion is true, but the reason is false.

### Final Answer:
- The assertion (A) is true, and the reason (R) is false.