Answer:
The red blood cell shrinks
Step-by-step explanation:
According to the question, the solution the red blood cell was placed in has a concentrated salt solution, this implies that the solution is hypertonic i.e. high solute concentration in relation to the blood cell, or otherwise the red blood cell's content is hypotonic i.e. low solute concentration in relation to the extracellular solution.
Due to this difference in concentration between the cell and the external solution, an osmotic flow occurs. Osmosis is the movement of water from a region of low solute concentration/high solvent concentration to a region of high solute concentration/low solvent concentration through a semi-permeable membrane, which in this case is the membrane of the red blood cell. This osmotic gradient causes water to flow out of the red blood cell (where the solute concentration is low) to the extracellular solution (where the solute concentration is high).
Hence, the red blood cell loses water and shrinks or reduce in size.