I think unsaturated
because -
At 55°C, a saturated solution would contain 120 g of solute, NaNO3. (Notice, this point is exactly on the solute's curve). If, for example we mixed in 140 g of NaNO3 instead of 110 g of solute at 55°C, we would create a SUPER saturated solution, because we would be at a point ABOVE the solute's solubility curve.
