The food vacuole digests the food. Wastes and excess water are transported outside the cell by contractile vacuoles. An amoeba, a single-celled organism lacking internal organs, is shown approaching a much smaller paramecium, which it begins to engulf with large outflowings of its cytoplasm, called pseudopodia.

In Paramecium, which has one of the most complex contractile vacuoles, the vacuole is surrounded by several canals, which absorb water by osmosis from the cytoplasm....In Amoeba contractile vacuoles collect excretory waste , such as ammonia, from the intracellular fluid by both diffusion and active transport ...
Therefore, contractile vacuole found in both Paramecium and Amoeba proteus. That's why option 'C'is the correct answer.

Contractile vacuole found in Paramoecium and Amoeba Proteus

The contractile vacuole is a specialized organelle found in certain unicellular organisms, primarily in freshwater protists, to maintain osmoregulation and remove excess water from the cell. It acts as a water expulsion system by collecting and expelling water from the cell to prevent it from bursting due to osmotic pressure. The contractile vacuole plays a vital role in the survival and homeostasis of these organisms.

Contractile vacuole in Paramoecium:
Paramoecium is a genus of unicellular ciliates commonly found in freshwater environments. The contractile vacuole in Paramoecium is responsible for removing excess water from the cell. It collects water through a network of canals and vesicles scattered throughout the cytoplasm. These canals converge towards the contractile vacuole, which is usually located at the posterior end of the cell. The contractile vacuole periodically fills with water and then contracts, expelling the excess water through a pore in the cell membrane. This process helps maintain the osmotic balance and prevents the cell from swelling and potentially bursting.

Contractile vacuole in Amoeba Proteus:
Amoeba proteus is a type of amoeba that is also commonly found in freshwater environments. Similar to Paramoecium, Amoeba proteus possesses a contractile vacuole to regulate water content within the cell. The contractile vacuole in Amoeba proteus functions in a similar manner to that of Paramoecium. It collects excess water from the cytoplasm through a network of canals and vesicles and then contracts to expel the water out of the cell. The contractile vacuole in Amoeba proteus is typically located near the posterior end of the cell, and its activity is essential for maintaining the cell's osmotic balance.

Conclusion:
In conclusion, the contractile vacuole is found in both Paramoecium and Amoeba proteus. These unicellular organisms utilize this organelle to regulate water content within the cell and prevent it from bursting due to osmotic pressure. The contractile vacuole is a crucial adaptation for survival in freshwater environments where these organisms reside.