Which of the following statements are correct about the reaction between the copper metal and dilute $HNO_3$?
$(I)$ The principal reducing product is $NO$ gas.
$(II)$ $Cu$ metal is oxidised to $Cu^{2+}$ (aq.) ion which is blue in colour.
$(III)$ $NO$ is paramagnetic and has one unpaired electron in antibonding molecular orbital.
$(IV)$ $NO$ reacts with $O_2$ to produce $NO_2$ which is linear in shape.
Choose the correct statements.

• A
  $I, II, III$
• B
  $I, III$
• C
  $II, IV$
• D
  All the above