$a\text{C}_2\text{O}_4^{2-} + b\text{MnO}_4^- + c\text{H}^+ \rightarrow x\text{Mn}^{2+} + y\text{H}_2\text{O} + z\text{CO}_2$
$a$ and $x$ respectively are

Given below are two statements.
Statement-I: In $\text{H}_2\text{O}_2$, each oxygen atom is assigned an oxidation number of $-1$, in $\text{RbO}_2$ each oxygen atom is assigned an oxidation number of $-\dfrac{1}{2}$.
Statement-II: Representation of $\text{HAuCl}_4$ and $\text{MnO}_2$ in stock notation is $\text{HAu(III)Cl}_4$ and $\text{Mn(II)O}_2$, respectively.
Examine the above statements and choose the correct answer.

$$ \text { Match List-I with List-II } $$

List-I (Types of redox reactions)	List-II (Examples)
a. Combination reaction	i. ${\mathrm{Cl}}_{2(\mathrm{g})}+2{\mathrm{Br}}_{(\mathrm{aq})}^{-}\to 2{\mathrm{Cl}}_{(\mathrm{aq})}^{-}+{\mathrm{Br}}_{2(1)}$${\mathrm{Cl}}_{2(\mathrm{g})}+2{\mathrm{Br}}_{(\mathrm{aq})}^{-}\to 2{\mathrm{Cl}}_{(\mathrm{aq})}^{-}+{\mathrm{Br}}_{2(1)}$Cl_(2(g))+2Br_((aq))^(-)rarr2Cl_((aq))^(-)+Br_(2(1))
b. Decomposition reaction	ii. $2{\mathrm{H}}_2{\mathrm{O}}_{2(\mathrm{aq})}\to 2{\mathrm{H}}_2{\mathrm{O}}_{(\mathrm{l})}+{\mathrm{O}}_{2(\mathrm{g})}$$2{\mathrm{H}}_2{\mathrm{O}}_{2(\mathrm{aq})}\to 2{\mathrm{H}}_2{\mathrm{O}}_{(\mathrm{l})}+{\mathrm{O}}_{2(\mathrm{g})}$2H_(2)O_(2(aq))rarr2H_(2)O_((l))+O_(2(g))
c. Displacement reaction	iii. ${\mathrm{CH}}_{4(\mathrm{g})}+2{\mathrm{O}}_{2(\mathrm{g})}\stackrel{\mathrm{\Delta }}{\to }{\mathrm{CO}}_{2(\mathrm{g})}+2{\mathrm{H}}_2{\mathrm{O}}_{(\mathrm{l})}$${\mathrm{CH}}_{4(\mathrm{g})}+2{\mathrm{O}}_{2(\mathrm{g})}\stackrel{\mathrm{\Delta }}{\to }{\mathrm{CO}}_{2(\mathrm{g})}+2{\mathrm{H}}_2{\mathrm{O}}_{(\mathrm{l})}$CH_(4(g))+2O_(2(g))rarr"Delta"CO_(2(g))+2H_(2)O_((l))
d. Disproportionation reaction	iv. $2{\mathrm{H}}_2{\mathrm{O}}_{(1)}\stackrel{\mathrm{\Delta }}{\to }2{\mathrm{H}}_{2(\mathrm{g})}+{\mathrm{O}}_{2(\mathrm{g})}$$2{\mathrm{H}}_2{\mathrm{O}}_{(1)}\stackrel{\mathrm{\Delta }}{\to }2{\mathrm{H}}_{2(\mathrm{g})}+{\mathrm{O}}_{2(\mathrm{g})}$2H_(2)O_((1))rarr"Delta"2H_(2(g))+O_(2(g))

$$ \text { Choose the correct answer from the options given below. } $$