Correct Answer:
A. Constant
The correct answer is Constant. Mass is an intrinsic property of an object, representing the amount of matter it contains. It does not change with location, gravitational field, or acceleration. While an object's weight (which is mass multiplied by the acceleration due to gravity) would be zero at the Earth's center due to zero net gravitational force, its mass remains unchanged.
- 'Same as on the surface' would be true for mass, but the question implies a change, and weight would be different.
- 'Doubled' or 'Half of surface value' are incorrect as mass is invariant.
Therefore, the mass of a body is constant regardless of its position, even at the Earth's center.