In which of the following reactions, $\mathrm{NO}_2$ is not liberated?

• Correct answer
  A

  $\mathrm{Zn}+(\text { dil }) \mathrm{HNO}_3 \rightarrow$
• B

  $\mathrm{I}_2+\text { (conc.) } \mathrm{HNO}_3 \rightarrow$
• C

  $\mathrm{Cu}+\text { (conc.) } \mathrm{HNO}_3 \rightarrow$
• D

  $\mathrm{C}+\text { (conc. }) \mathrm{HNO}_3 \rightarrow$

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