Molar mass of a diacidic base is 40g. Density of its aqueous solution is 1 g/ cc. More concentrated solution among the following is

(1) 1 M solution means      1 mole (40 g) of solute dissolved in 1000 ml solution      Wsolute=40 g; Vsolution=1000 ml Wsolution=V×d Wsolution=1000 g  Wsolvent=(1000-40)g=960 g(2) 1 molal solution means      1 mole (40) g solute in 1000 g solvent        Wsolute=40 g; Wsolvent=1000 g;(3) 1 N solution means       1 GEW (20 g) of solute in 1000 ml solution       Wsolute=20 g; Wsolvent=980 g;(4) 1 % wv solution means        Wsolute=1 g ; Vsolution=100 ml ; Wsolution=100 g ; Wsolvent=99 g ;Comparing all the solution1 M .   .   .   40 g of solute .   .   .   960 g of solvent1 m .   .   .   40 g of solute .   .   .   1000 g of solvent1 N .   .   .   40 g of solute .   .   .   1960 g of solvent1 %wv .   .   .   40 g of solute .   .   .   3960 g of solvent∴1 M is most concentrated.