Write the unit of mass in nuclear physics and define it and it is equivalent to how many kilograms?

$A$ deuteron is bombarded on an $_8O^{16}$ nucleus and an $\alpha$-particle is emitted. The product nucleus is

Give one example each of central force and non-central force.

The radius $R$ of a nucleus of mass number $A$ can be estimated by the formula $R = (1.3 \times 10^{-15}) A^{1/3} \; m$. It follows that the mass density of a nucleus is of the order of $(M_{\text{prot}} \cong M_{\text{neut}} = 1.67 \times 10^{-27} \; kg)$.

Read the following statements:
$(A)$ Volume of the nucleus is directly proportional to the mass number.
$(B)$ Volume of the nucleus is independent of mass number.
$(C)$ Density of the nucleus is directly proportional to the mass number.
$(D)$ Density of the nucleus is directly proportional to the cube root of the mass number.
$(E)$ Density of the nucleus is independent of the mass number.
Choose the correct option from the following options.

What is the approximate percentage of the total mass of an atom that is concentrated in its nucleus (in $\%$)?