Final answer:
The correct answer is hypertonic. A hypertonic solution causes water to leave the cell, resulting in cell shrinkage or crenation. This occurs because the solute concentration is higher outside the cell than inside. Therefore, the correct answer to the question is (b) Hypertonic.
Step-by-step explanation:
When a cell is dropped into a saltwater solution and shrivels up, you can infer that the type of saltwater solution is hypertonic compared to the cell.
A hypertonic solution has a higher concentration of solutes outside the cell than inside its cytoplasm. As a result, water moves out of the cell toward the area of higher solute concentration, leading to the cell shrinking or creating.
In contrast, if the solution were hypotonic, water would move into the cell, causing it to swell. An isotonic solution would mean the solute concentration is equal inside and outside of the cell, resulting in no net change in the cell's volume. Therefore, the correct answer to the question is (b) Hypertonic.