A galvanic cell is constructed using the redox reaction, $\frac{1}{2} \mathrm{H}_{2}(g)+\operatorname{AgCl}(s) \rightleftharpoons \mathrm{H}^{+}(a q)+\mathrm{Cl}^{-}(a q)+\operatorname{Ag}(s)$ it is represented as

• A

  $\mathrm{Pt}\left|\mathrm{H}_{2}(g)\right| \mathrm{HCl}(\mathrm{sol})|| \mathrm{AgNO}_{3}(\mathrm{sol}) \mid \mathrm{Ag}$
• B

  $\operatorname{Ag}|\operatorname{AgCl}(s)| \mathrm{KCl}(\mathrm{sol})|| \mathrm{HCl}(\mathrm{sol}), \mathrm{H}_{2}(\mathrm{~g}) \mid \mathrm{Pt}$
• C

  $\mathrm{Pt}\left|\mathrm{H}_{2}(g)\right| \mathrm{KCl}(\operatorname{sol}) \| \operatorname{AgCl}(s) \mid \mathrm{Ag}$
• Correct answer
  D

  $\mathrm{Pt}\left|\mathrm{H}_{2}(g), \mathrm{HCl}(\operatorname{sol})\right||\operatorname{AgCl}(s)| \mathrm{Ag}$

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