The correct option is D More pronounced inert pair effect in lead than in Ge
The pair of electrons in valence s−orbital is reluctant to take part in bond formation due to poor shielding effect of d− and f− electron in heavier elements. This is known as inert pair effect.
It is generally observed in post transition metal compounds.
More pronounced inert pair effect is in lead than in Ge.
So, Pb tends to be in +2 oxidation state where as Ge is stable in +4 oxidation state.
Hence, Pb(IV) compounds are reduced to Pb(II) and acts as strong oxidants.
Ge(II) compounds are oxidised to Ge(IV) and acts as powerful reducing agents.