Observe the following reactions I. $\mathrm{N}_2(\mathrm{~g})+3 \mathrm{H}_2(\mathrm{~g}) \xrightarrow[\substack{773 \mathrm{~K} \\ 200 \mathrm{~atm}}]{\mathrm{X}} 2 \mathrm{NH}_3(\mathrm{~g})$ II. $\mathrm{CO}(\mathrm{g})+\mathrm{H}_2 \mathrm{O}(\mathrm{g}) \frac{\mathrm{Y}}{673 \mathrm{~K}} \rightarrow \mathrm{CO}_2(\mathrm{~g})+\mathrm{H}_2(\mathrm{~g})$ III. $\mathrm{CH}_4(\mathrm{~g})+\mathrm{H}_2 \mathrm{O}(\mathrm{g}) \xrightarrow[1270 \mathrm{~K}]{\mathrm{Z}} \mathrm{CO}(\mathrm{g})+3 \mathrm{H}_2(\mathrm{~g})$ Catalysts X, Y, Z respectively are

• A

  Iron, sodium arsenite, cobalt
• B

  Iron, zinc, cobalt
• C

  Cobalt, zinc, nickel
• Correct answer
  D

  Iron, iron chromate, nickel

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