Can someone please help me on this question?

The model below represents water.

~insert picture~

Based on the labels, what is the best description of this model?

A. X and Y represent molecules; Z represents an atom of water

B. X represents a molecule; Y represents a particle; Z represents an atom of water

C. X represents an atom; Y represents a molecule; Z represents a particle of water

D. X and Y represent atoms; Z represents a molecule of water