A : If an object is taken to the centre of earth, then its centre of gravity cannot be defined.
R : At the centre of earth acceleration due to gravity is zero.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion,
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion,
C. If Assertion is true statement but Reason is false,
D. If both Assertion and Reason are false statements,

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that if an object is taken to the center of the Earth, then its center of gravity cannot be defined.
- The center of gravity is the point where the weight of the object can be considered to act.

2. **Understanding the Reason (R)**:
- The reason states that at the center of the Earth, the acceleration due to gravity is zero.
- The acceleration due to gravity (g) is what causes weight (W) to be defined as W = mg, where m is the mass of the object.

3. **Analyzing the Situation at the Center of the Earth**:
- At the center of the Earth, the gravitational forces from all parts of the Earth cancel each other out. Therefore, the net gravitational force acting on an object at this point is zero.
- Since weight is defined as the force due to gravity (W = mg), if g = 0, then W = 0. This means that the object has no weight at the center of the Earth.

4. **Conclusion about the Assertion**:
- Since the weight of the object is zero at the center of the Earth, we cannot define a center of gravity for the object. Thus, the assertion (A) is true.

5. **Conclusion about the Reason**:
- The reason (R) correctly explains why the assertion (A) is true. Since the acceleration due to gravity is indeed zero at the center of the Earth, the reason is also true.

6. **Final Evaluation**:
- Both the assertion (A) and the reason (R) are true, and the reason correctly explains the assertion. Therefore, the correct conclusion is that both statements are true, and the reason is the correct explanation of the assertion.

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

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