Final answer:
Crenation occurs in red blood cells when they are placed in a hypertonic solution option(3), where they lose water and shrink due to the higher concentration of solutes outside of the cell.
Step-by-step explanation:
Crenation is likely to occur in blood cells in a hypertonic solution. A hypertonic solution has a higher concentration of solutes compared to the inside of the red blood cells. As a result, water exits the cell in an attempt to balance the solute concentrations on both sides of the cell membrane, leading to the cell shrinking or creating.
Red blood cells in an isotonic solution will maintain their normal shape since the solute concentration is equal inside and outside of the cells, leading to no net movement of water. In a hypotonic solution, the opposite occurs; red blood cells can swell and potentially burst due to excess water entering the cells, a process known as hemolysis.