When you eat a salty snack like potato chips, the concentration of salt outside your cells in your mouth increases. This creates a hypertonic environment relative to the inside of the cells. As a result, water will move out of the cells in an attempt to balance the concentration of solutes (salt) inside and outside the cells. This loss of water causes the cells to shrink.
Therefore, the correct answer is:
c water moves out of the cell causing them to shrink.