Assertion (A) :$P{b}^{+4}$ compounds are stronger oxidiising agents than $S{n}^{4+}$ compounds .
Reason (R): The higher oxidation states for group $14$ elements are more stable for the heavier members of the group due to inert pair effect .

Answer: CSolution: Statement I is true. Stronger oxidising agent is one which itselt can easily be reduced. $P{b}^{4+}$ is unstable, due to inert pair effect, can easily be reduced to stable $P{b}^{2+}$, hence a stronger oxidising agent than $S{n}^{4+}$
Statement II is false. Due to inert pair effect, the higher oxidatioin states of group 14 elements becomes less stable for heavier member.