A: Blood group analysis shows the human beings are more closely related to apes than to monkeys.
R: The blood groups A and B are found in apes but not in monkeys.

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 but 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 falses statements, then mark (4)

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion (A):**
- The assertion states that blood group analysis indicates that humans are more closely related to apes than to monkeys. This is based on genetic and blood group studies that show similarities between humans and apes.

2. **Evaluating the Truth of the Assertion:**
- The assertion is true. Studies have shown that humans and apes share a closer genetic relationship compared to humans and monkeys. This is supported by similarities in chromosome numbers and genetic markers.

3. **Understanding the Reason (R):**
- The reason states that blood groups A and B are found in apes but not in monkeys. This suggests a specific genetic trait that differentiates apes from monkeys in terms of blood group classification.

4. **Evaluating the Truth of the Reason:**
- The reason is also true. In fact, blood groups A and B are indeed present in apes, whereas certain monkeys primarily exhibit the Rhesus factor (R factor), which is a different classification.

5. **Determining the Relationship Between Assertion and Reason:**
- Since both the assertion and the reason are true, and the reason provides a correct explanation for the assertion (as it highlights a key genetic difference that supports the assertion), we conclude that the reason is a valid explanation for the assertion.

6. **Final Conclusion:**
- Both the assertion and reason are true, and the reason correctly explains the assertion. Therefore, the answer is option A: both assertion and reason are true, and reason is the correct explanation.