How would you expect osmosis to affect the water balance in these organisms?

The water balance is the relation or balance between the amount of water entering the organism by intake liquids and food and the total output or loss of water lost from the body by different ways such as the kidneys, lungs, bowels, and skin.

Other than water there is the constant input of electrolytes also occurs into the system. Osmotic pressure and the process of osmosis help in ensuring that optimal concentrations of electrolytes and non-electrolytes are maintained in the cells. The excess water or electrolytes, move out of the cells by the osmosis through the semi-permeable membrane that is the cell membrane here.

if you listed your answers right then i believe your answer is b.