Here's a problem to solve: A forecast for "wintry mix" indicates that vapor in the air will form both rain and snow. Which of these is a correct principle illustrated by this event?

Among the 4 following options, which is the correct answer?

- A: There is little water in the atmosphere of Earth.
 
- B: Most water on Earth is found as vapor.
 
- C: Water exists in all three states on Earth.
 
- D: Water on Earth tends to form a solid over time.
 