${\mathrm{PbO}}_2$ is obtained from
 

• A

  the reaction of $\mathrm{PbO}$ with $\mathrm{HCl}$
   
• B

  thermal decomposition of $\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2$ at $200°\mathrm{C}$
   
• Correct answer
  C

  the reaction of ${\mathrm{Pb}}_3{\mathrm{O}}_4$ with ${\mathrm{HNO}}_3$
   
• D

  the reaction of $\mathrm{Pb}$ with air at room temperature

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