The correct option is C Contractile vacuole
Vacuole is the membrane-bound space found in the cytoplasm. It contains water, sap, excretory product and other materials not useful for the cell. The vacuole is bound by a single membrane called tonoplast. Some vacuoles like the contractile vacuole of Amoeba is important for excretion. In many cells, as in protists, food vacuoles are formed by engulfing the food particles. The food vacuole helps in digestion of the food. Wastes and excess water are expelled outside the cell by contractile vacuoles.