Which of the following values is the correct order of nuclear density?

The mass number and the volume of a nucleus are $A$ and $V$ respectively. If the mass number is increased to $2A$,then the volume changes to:

Nuclei with magic numbers of protons $Z = 2, 8, 20, 28, 50, 82$ and magic numbers of neutrons $N = 2, 8, 20, 28, 50, 82, 126$ are found to be very stable.
$(i)$ Verify this by calculating the proton separation energy $S_p$ for $^{120}Sn$ $(Z = 50)$ and $^{121}Sb$ $(Z = 51)$. The proton separation energy for a nuclide is the minimum energy required to separate the least tightly bound proton from a nucleus of that nuclide. It is given by $S_p = (M_{Z-1, N} + M_H - M_{Z, N})c^2$. Given:
$^{119}In = 118.9058 \ u, ^{120}Sn = 119.902199 \ u, ^{121}Sb = 120.903824 \ u, ^1H = 1.0078252 \ u$
$(ii)$ What does the existence of magic numbers indicate?

$A$ nucleus with atomic mass number $A$ produces another nucleus by losing $2$ alpha particles. The volume of the new nucleus is $60$ times that of the alpha particle. The atomic mass number $A$ of the original nucleus is:

$1\,U = ...... \text{kg}$. How is the mass of an atom or nucleus determined?

If the radius of $_{13}^{27}Al$ is $3.6 \ fm$,then the radius of the $_{52}^{125}Te$ nucleus will be ........ $fm$.