Answer:
(a) Cell wall
Step-by-step explanation:
A hypotonic solution has less solute compared to the plant cell. When plant cell is kept inside it, water will start to move along concentration gradient from outside to inside the cell. Cell will start swelling but it will not burst due to presence of cell wall.
The strong and rigid structure of cell wall prevents the cell from bursting. The pressure inside called as turgor pressure will rise against the cell wall till it becomes equal to the outside pressure after which there will be no more intake of water.