If $m$ is the mass of the $_Z{X^A}$ nucleus,and $m_n$ and $m_p$ are the masses of a neutron and a proton respectively,then which of the following is correct?

The mass of an $\alpha$-particle is

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A:$ The binding energy per nucleon is practically independent of the atomic number for nuclei of mass number in the range $30$ to $170$.
Reason $R:$ Nuclear force is short-ranged.
In the light of the above statements, choose the correct answer from the options given below:

The energy equivalent to $1\,mg$ of matter in $MeV$ is

List-$I$ shows various functional dependencies of energy $(E)$ on the atomic number $(Z)$. Energies associated with certain phenomena are given in List-$II$. Choose the option that describes the correct match between the entries in List-$I$ to those in List-$II$.

List-$I$	List-$II$
$(P) \ E \propto Z^2$	$(1)$ energy of characteristic $x-$rays
$(Q) \ E \propto (Z-1)^2$	$(2)$ electrostatic part of the nuclear binding energy for stable nuclei with mass numbers in the range $30$ to $170$
$(R) \ E \propto Z(Z-1)$	$(3)$ energy of continuous $x-$rays
$(S) \ E$ is practically independent of $Z$	$(4)$ average nuclear binding energy per nucleon for stable nuclei with mass number in the range $30$ to $170$
	$(5)$ energy of radiation due to electronic transitions from hydrogen-like atoms

We are given the following atomic masses:
$^{238}_{92}U = 238.05079 \; u$
$^{4}_{2}He = 4.00260 \; u$
$^{234}_{90}Th = 234.04363 \; u$
$^{1}_{1}H = 1.00783 \; u$
$^{237}_{91}Pa = 237.05121 \; u$
Here,the symbol $Pa$ represents the element protactinium $(Z=91)$.
$(a)$ Calculate the energy released during the alpha decay of $^{238}_{92}U$.
$(b)$ Show that $^{238}_{92}U$ cannot spontaneously emit a proton.