Pick out the correct statement from the following.

$A$ nucleus has mass number $\alpha$ and radius $R_{\alpha}$. Another nucleus has mass number $\beta$ and radius $R_{\beta}$. If $\beta = 8\alpha$, then $R_{\alpha}/R_{\beta}$ is:

$(a)$ Two stable isotopes of lithium $_{3}^{6} Li$ and $_{3}^{7} Li$ have respective abundances of $7.5 \%$ and $92.5 \%$. These isotopes have masses $6.01512 \; u$ and $7.01600 \; u$,respectively. Find the atomic mass of lithium.
$(b)$ Boron has two stable isotopes,$_{5}^{10} B$ and $_{5}^{11} B$. Their respective masses are $10.01294 \; u$ and $11.00931 \; u$,and the atomic mass of boron is $10.811 \; u$. Find the abundances of $_{5}^{10} B$ and $_{5}^{11} B$.

Nuclear forces are

$A$ nucleus splits into two nuclear fragments. If the ratio of their velocities is $2:1$,then the ratio of their nuclear radii is:

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.