Assertion : Population of India crossed 1 billion in May 2000.
Reason : It is the result of rapid decline in death rate, maternal mortality rate (MMR), and infant mortality rate (IMR) as well as an increase in the number of people in reproducible age.

Options

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

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that the population of India crossed 1 billion in May 2000. This is a factual statement and can be verified with historical data.

2. **Understanding the Reason**:
- The reason provided explains that the increase in population is due to a rapid decline in death rates, maternal mortality rates (MMR), and infant mortality rates (IMR), along with an increase in the number of people in the reproductive age group.

3. **Analyzing the Relationship**:
- The assertion is true; India’s population did indeed cross 1 billion in May 2000.
- The reason is also true; the decline in death rates, MMR, and IMR, as well as an increase in the reproductive age population, contributed to this population growth.

4. **Determining the Correct Explanation**:
- The reason provided correctly explains why the assertion is true. The demographic changes mentioned in the reason are directly linked to the population growth stated in the assertion.

5. **Final Conclusion**:
- Since both the assertion and reason are true, and the reason correctly explains the assertion, we conclude that the answer is option 1: "Both assertion and reason are true, and reason is the correct explanation of the assertion."

### Final Answer:
Option 1: Both assertion and reason are true, and reason is the correct explanation of the assertion.

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