During the formation of snowflake, water freezes, the random motion of water molecules is transformed into the orderly arrangement of a crystal. The entropy of the water molecules in the snowflake decrease due to the orderly arrangement. In the formation of snow flake, heat energy must be transferred from water to the surrounding air. The entropy of air increase by more than the entropy of water plus air system increases. Hence, the entropy of water plus air system increases.
Therefore, the correct answer is option .