In which of the following reactions,$NO_2$ is not liberated?

• A
  $Zn + (\text{dil.}) HNO_3 \rightarrow$
• B
  $I_2 + (\text{conc.}) HNO_3 \rightarrow$
• C
  $Cu + (\text{conc.}) HNO_3 \rightarrow$
• D
  $C + (\text{conc.}) HNO_3 \rightarrow$