What is responsible for the formation of water on earth.

A. From the sun

B. Volcanic outgassing

C. Always had water

D. Collisions with meteors

volcanic outgassing.

The best answer would be option D.

Explanation:

scientists and researchers have found that comets and asteroids both can contain ice. They might have delivered a great amount of water to the earth if they had a collision with earth.

Researchers found recently that the ratio of different forms of hydrogen in meteors or asteroids appear to match what we find here on Earth.

Thus, the correct answer would be option D.