Because molecules will move from one side to another to come to an equilibrium, or balance of concentration, the moves from side B to side A, so the water level on side A goes .

Water, up

Explanation:

In the process of movement water in the diffusion of water the net movement of water goes from higher concentration to the low concentration area. The movement of water  move form one side to other side until it reaches an equilibrium and the level of water on the other side goes up.

Hence, the water molecule will move from from side B to side A until it reaches equilibrium and the water level on side A goes up.