What occurs when ice forms extracellularly in response to mild temperatures?

In the context of ice forming extracellularly in response to mild temperatures, the correct answer highlights the physiological response of cells to changes in their environment. When ice forms in the extracellular space, it leads to an increase in the concentration of solutes outside the cell, creating a hypertonic environment. Water within the cells will move outwards in an attempt to balance the solute concentrations. This movement of water results in the shrinking of the cells, a phenomenon known as crenation.

Crenation occurs because the osmotic pressure differential causes water to exit the cell, leading to a reduction in cell volume. This is particularly relevant in scenarios where ice formation occurs, as it can exacerbate the hypertonic conditions surrounding the cells. The focus here is on the cellular response to the increased extracellular solute concentration caused by freezing, which is why the option pertaining to cell shrinking due to hypertonic stress is the appropriate choice.