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 nucleus of $\sim 1.5 \times 10^{-3} \mathrm{pm}$ size.

Reason R : Proton $\left(\mathrm{H}^{+}\right)$ always exists in combined form.

In the light of the above statements, choose the most appropriate answer from the options given below:

1. A Both $\mathbf{A}$ and $\mathbf{R}$ are correct and $\mathbf{R}$ is the correct explanation of $\mathbf{A}$
2. B A is correct but R is not correct
3. C A is not correct but R is correct
4. D Both $\mathbf{A}$ and $\mathbf{R}$ are correct but $\mathbf{R}$ is NOT the correct explanation of $\mathbf{A}$ Correct answer