Final answer:
Red blood cells will crenate in a hypertonic solution due to the higher solute concentration outside the cell, which causes water to flow out of the cell.
Step-by-step explanation:
The red blood cells will undergo crenation when they are placed in a hypertonic solution. In a hypertonic solution, the solute concentration outside the cells is higher than inside, causing water to flow out of the cells. This results in the red blood cells shrinking as water leaves the cell, leading to crenation. Contrary to this, in a hypotonic solution, red blood cells would swell and could burst, a process known as hemolysis. And in an isotonic solution, red blood cells would retain their normal shape because the solute concentration is balanced, resulting in an equal flow of water in and out of the cells.