The correct option is D Pure water and soil solution
During absorption, there is a concentration gradient between cell sap and soil solution. At the time of absorption, concentration of water in the cell is less than soil solution, so at this time the water potential of cell sap will be lower than that of soil solution. Water potential of every solution is lower than that of pure water because pure water has highest water potential. So, during absorption of water by roots, the water potential of cell sap is lower than that of pure water and soil solution.