Q. It is because of inability of ns² electrons of the valence shell to participate in bonding that :

Answer of this question "It is because of inability of ns² electrons of the valence shell to participate in bonding that :", here are 4 choices for this question : Sn² is reducing while Pb²⁺ is oxidizing, Sn² and oxidising Pb⁴⁺ is reducing , Sn² and Pb²⁺ are both oxidising and reducing, Sn⁴⁺ is reducing while Pb⁴⁺ is oxidising.
Answer Is "Sn² is reducing while Pb²⁺ is oxidizing".