Depression in freezing point is a colligative property, thus higher the number of particles of solute in a solution, higher is the freezing point. Since, here the concentrations of solutions are also different. Thus, the solution with higher concentration possesses maximum depression in freezing point and hence, has the lowest freezing point.
Among the given, 0.01mNaCl possess maximum depression in freezing point and thus. has the lowest freezing point.