Number of moles of $ MnO_4^-$ required to oxidise one mole of ferrous oxalate completely in acidic medium will be :

Question

$\begin {array} {1 1} (1)\;0.2\: moles & \quad (2)\;0.6\: moles \\ (3)\;0.4\: moles & \quad (4)\;7.5\: moles \end {array}$