Among the following, the best which describes the concentration of solution formed by dissolving 4 g of  NaOH in 1 kg of water

GMW of NaOH$=40\text{g}$

Weight of water ,$\text{W}=1\text{kg}$

Molality of solution will find as follows:

            $\text{m}=\frac{\text{weight}\text{of solute}}{\text{GMW}\text{of solute}}\times \frac{1}{\text{Weight of solvent in kg}}$

Now, substitute the data in the above equation and then find molality.

             $\text{m}=\frac{4}{40}\times \frac{1}{1}=0.1$

Therefore, the concentration of solution is 0.1 m.