The correct answer to this question is D. The fourth diagram is the one which correctly depicts water molecules forming hydrogen bonds with each other. A hydrogen bond is a chemical bond between water molecules. This bond holds the mass of the molecules together.
While hydrogen bonds are weak, the large number of them present in water allows them to determine its chemical properties. Water is one of the most important hydrogen-bonds. It forms in water when the hydrogen atoms of a water molecule are attracted to an oxygen atom of another close water molecule. This bond makes water unique.