Introduction:
Celestial bodies are objects that exist in space and are part of the universe. They can be natural or artificial. Natural celestial bodies are those that occur naturally in space, such as the Sun, Moon, and stars. Artificial celestial bodies are human-made objects that are launched into space, such as satellites and spacecraft.

Explanation:
The correct answer is option 'D' - All of the above. Let's discuss each option in detail:

1. Sun: The Sun is a star and the central celestial body in our solar system. It is a massive ball of hot gases that emits light and heat. The Sun is essential for life on Earth as it provides energy for photosynthesis and helps maintain a stable climate.

2. Moon: The Moon is Earth's natural satellite. It is a celestial body that orbits around the Earth. The Moon is responsible for the tides on Earth and also plays a significant role in regulating the Earth's rotation and stability.

3. Stars: Stars are luminous celestial bodies that are composed of hot gases, primarily hydrogen and helium. They emit light and heat through a process called nuclear fusion. Stars are scattered throughout the universe and exist in various sizes, colors, and stages of their life cycle.

All three options, Sun, Moon, and Stars, are examples of celestial bodies. The Sun is a star, the Moon is Earth's natural satellite, and stars are distant luminous objects. They are essential components of our universe and have significant effects on our planet and beyond.

Conclusion:
Celestial bodies are objects that exist in space and are part of the universe. The Sun, Moon, and stars are examples of natural celestial bodies. They play vital roles in various astronomical phenomena and have a significant impact on our planet and the entire universe.