Here's a problem to solve: A student observes zinc turning from a solid to a liquid in a laboratory investigation. Which statement describes the change in zinc atoms while melting?

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

- A: The mass of the zinc atoms decreased.
 
- B: The zinc atoms lost their relative fixed position.
 
- C: The zinc atoms were changed into atoms of another element.
 
- D: The size of the zinc atoms decreased.
 