Final answer:
The mass of a moving object remains unchanged.
Step-by-step explanation:
The correct answer is C. It remains unchanged.
The mass of a moving object does not change with its speed. Mass is an intrinsic property of an object and does not depend on its motion. Therefore, the mass remains unchanged.
For example, consider a car moving at a constant speed. The car's mass does not increase or decrease due to its motion. It remains the same regardless of how fast or slow the car is moving.
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