Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R:$
Assertion $A:$ Metallic sodium dissolves in liquid ammonia giving a deep blue solution,which is paramagnetic.
Reason $R:$ The deep blue solution is due to the formation of amide.
In the light of the above statements,choose the correct answer from the options given below:

• A
  $A$ is false but $R$ is true
• B
  Both $A$ and $R$ are true and $R$ is the correct explanation of $A$
• C
  Both $A$ and $R$ are true but $R$ is $NOT$ the correct explanation of $A$
• D
  $A$ is true but $R$ is false