Answer: The correct answer for the blank is- hypertonic solution.
A hypertonic solution is the one that contains higher solute concentration as compared to solvent. When a cell is placed in hypertonic solution, it will loose water through osmosis ( as water always moves from an area of low solute concentration to an area where solute concentration is comparatively higher).
Thus, animal cell will shrink ( due to loss of water) when placed in a hypertonic solution.