The correct option is
D Exosmosis
Wilting is a condition when the amount of water lost from the plant during transpiration is greater the amount of water absorbed from the soil. Due to high rate of transpiration the cell loses water by exosmosis. Wilting is the loss of rigidity of non-woody parts of the plants. This occurs when the turgor pressure in non-lignified plant cells falls towards zero, as a result of diminished water in the cells.
So, the correct answer is option C.