The equivalent weight of which of the following is maximum?
(Given: atomic weights Na=23, Mn=55, Cr=52, K=19, O=16, C=12 )

Molar mass of ${\mathrm{Na}}_2{\mathrm{C}}_2{\mathrm{O}}_4\cdot 2{\mathrm{H}}_2\mathrm{O}$ is 134 g/mol and its equivalent weight is 67 g/mol

Equivalent weight of ${\mathrm{KMnO}}_4\mid {\mathrm{H}}^{+}$ is 31.6 g/mol and ${\mathrm{KMnO}}_4\mid {\mathrm{H}}_2\mathrm{O}$ is 52.66 g/mol

Equivalent weight of ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7\mid {\mathrm{H}}^{+}$ is 49 g/mol