Answer:
C Hydrogen bonding is the main force that attracts water molecules to 
one another.
Step-by-step explanation:
Hydrogen bonding affects water molecules because, it is the main force which holds and attracts water molecules to one another. 
- Hydrogen bonding is an intermolecular force.
 - Intermolecular forces holds molecules together. Examples are van der waals forces, hydrogen bonding. 
 - In a hydrogen bonding, hydrogen of one molecule electrostatically combines with a more electronegative specie usually nitrogen, flourine and oxygen on another atom. 
 - This attraction results in hydrogen bonding between two or more molecules. 
 - The unique and anomalous behavior of water is as a result of these hydrogen bonds between its molecules.