Which of the following oxidation states are the most characteristic for lead and tin respectively?

Elements of group $14$:

In the following reaction,identify the nature of the product formed by the complete hydrolysis of the underlined atom at $R.T.$:
$\underline{P}_4 + H_2O \longrightarrow$ No reaction

In the following reaction,identify the nature of the product formed by the complete hydrolysis of the underlined atom at $R.T.$:
$\underline{P}_4O_{10} + H_2O \longrightarrow H_3PO_4$

Which are the various forms of silica?

It is observed that $Pb^{2+}$ is more stable than $Pb^{4+}$, while $Sn^{2+}$ is less stable than $Sn^{4+}$. Consider the following reactions:
$PbO_{2} + Pb \rightarrow 2PbO; \Delta_{r}G^{\circ} (1)$
$SnO_{2} + Sn \rightarrow 2SnO; \Delta_{r}G^{\circ} (2)$
Identify the correct set from the following.