Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: Loss of electron from hydrogen atom results in a nucleus of $\sim 1.5 \times 10^{-3} \ pm$ size.
Reason $(R)$: Proton $(H^+)$ always exists in combined form.
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
  $A$ is correct but $R$ is not correct.
• C
  $A$ is not correct but $R$ is correct.
• D
  Both $A$ and $R$ are correct but $R$ is $NOT$ the correct explanation of $A$.