The unbalanced chemical reactions given in List I show missing reagent or condition (?) which are provided in list II. match List I with List II and select the correct answer using the code given below the lists :
 

	List I		List II
A.	${\text{PbO}}_2+\mathrm{H}{}_2{\text{SO}}_4\stackrel{\text{?}}{⟶}{\text{PbSO}}_4+{\text{O}}_2+\text{other product}$	P	$\mathrm{NO}$
B.	${\text{Na}}_2\mathrm{S}{}_2{\text{O}}_3+\mathrm{H}{}_2\text{O}\stackrel{\text{?}}{⟶}{\text{NaHSO}}_4+\text{other product}$	Q	${\mathrm{I}}_2$
C.	$\mathrm{N}{}_2\mathrm{H}{}_4\stackrel{\text{?}}{⟶}\mathrm{N}{}_2+\text{other product}$	R	Warm
D.	$\text{Xe}\mathrm{F}{}_2\stackrel{\text{?}}{⟶}\text{Xe}+\text{other product}$	S	${\mathrm{Cl}}_2$

• A

  a-p;b-r;c-q;d-s;
• B

  a-p;b-r;c-q;d-s;
• Correct answer
  C

  a-r;b-s;c-q;d-p;
• D

  a-r;b-q;c-s;d-p;

Hence, the correct answer is option: 'C'.