Given below are two statements: One is labelled as $Assertion$ $A$ and the other is labelled as $Reason$ $R$:
Assertion $A$: $pK_a$ value of phenol is $10.0$ while that of ethanol is $15.9$.
Reason $R$: Ethanol is a stronger acid than phenol.
In the light of the above statements,choose the correct answer from the options given below:

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