Assertion $A$: For an ideal solution formed by mixing liquids $P$ and $Q$, $\Delta_{mix} H = 0$ and $\Delta_{mix} V = 0$.
Reason $R$: No interactions occur between $P$ and $Q$.
In the light of the above statements, choose the most appropriate answer from the options given below:

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