The correct option is D Sn2+ is reducing while Pb4+ is oxidising
Inability of ns2 electrons of the valence shell to participate in bonding on moving down the group in heavier p-block elements is called inert pair effect
As a result, Pb(II) is more stable than Pb(IV)
Sn(IV) is more stable than Sn(II)
Pb(IV) is easily reduced to Pb(II)
So, Pb(IV) is oxidising agent
Sn(II) is easily oxidised to Sn(IV)
So, Sn(II) is reducing agent