The correct option is C 3
An+x=+n→AO−3x=+5 (undergoes oxidation)
∴ Number of e− released in oxidation =(5−n)
∴ Equivalent of MnO⊝4=4×(5−n)
Equivalents of MnO⊝4=1.6×5 (Mn(VII) is reduced to Mn(II) in acidic medium, therefore, oxidation state changes by 5).
∴4×(5−n)=1.6×5
∴n=3