The oxidation state of sulphur in the anions S2O2−4, S2O2−4 and S2O2−6 follows the order:
Oxidation state of S2O2−4
2(x)+4(−2)=−2
2x=8−2
2x=6
x=3
Oxidation state of SO2−3
x+3(−2)=−2
x=6−2
x=4
Oxidation state of S2O2−6
2(x)+6(−2)=−2
2x=12−2
2x=10
x=5
So the oxidation state of sulphur in the anions S2O2−4, S2O2−4 and S2O2−6 follows the order.S2O2−4<SO2−3<S2O2−6.
Hence option B is correct.