In a hypotonic solution, the solute concentration outside the cell is lower than inside the cell. As a result, water moves into the cell through osmosis in an attempt to equalize the solute concentrations. This influx of water causes the cell to swell and can potentially lead to cytolysis (bursting of the cell) if too much water enters.
Therefore, the correct response to what happens to the cell in a hypotonic solution is:
"The cell has more solute than its environment, so solvent moves from outside the cell to inside the cell, causing the cell to swell."