As the temperature of water increases, its viscosity

The correct option is Decreases.

Step-by-Step Explanation:
1. Definition of Viscosity: Viscosity is a measure of a fluid's resistance to flow or deformation. A liquid with high viscosity flows slowly, whereas a liquid with low viscosity flows easily.
2. Cohesive Forces in Liquids: In liquids, viscosity is determined by the strength of the cohesive forces (intermolecular attractions) holding the molecules together. In water, these cohesive forces are primarily due to hydrogen bonding.
3. Impact of Increasing Temperature: When water is heated, the thermal energy of its molecules increases, which causes them to vibrate and move more rapidly.
4. Weakening of Molecular Bonds: The increased kinetic energy allows the molecules to overcome the intermolecular cohesive forces holding them in place.
5. Conclusion: Since the intermolecular attractions weaken at higher temperatures, the water molecules can slide past each other more easily. As a result, the resistance to flow decreases, meaning the viscosity of water decreases as the temperature increases.