Glycerol would be expected to have the greatest solubility in polar solvents, with water being a primary example.
Glycerol is a polar molecule due to its three hydroxyl (OH) groups. As a general rule, polar substances tend to dissolve better in polar solvents, and nonpolar substances tend to dissolve better in nonpolar solvents. Glycerol is hydrophilic (water-attracting) because of its polar nature.
Therefore, glycerol would be expected to have the greatest solubility in polar solvents, with water being a primary example. Glycerol forms hydrogen bonds with water molecules, making it miscible in water and allowing for a high degree of solubility.