A) Water will move into the slug and its cells will swell until an equilibrium is reached.
B) Water will move out of the slug and its cells will shrink until an equilibrium is reached.
C) Water will move into and out of the slug equally. (Water concentrations are equal inside & outside the slug's cells, so it moves in and out equally with no apparent change visible.)
D) Water will first move into the slug, then will begin to move out.