Correct Answer - D
`[5e+MnO_(4)^(-)+8H^(+)rarrMn^(2+)+4H_(2)O…(i)]xx2`
`[C_(2)O_(4)^(2-)rarr 2e+2CO_(2)…(ii)]xx5`
`MnO_(4)^(-)+16H^(+)+5C_(@)O_(4)^(2-)rarr2Mn^(2+)+10CO_(2)`
As 2 moles of `MnO_(4)^(-)` required to oxidize 5 moles of oxalate.
So number of moles of `MnO_(4)^(-)` required to oxidize 1 mole of oxalate = 2/5=0.4.