A Neutron Star Has Approximately the Same Density as Nuclear $8.0 \mathrm{~km}$

A neutron star has approximately the same density as nuclear material. A typical neutron star has a radius of $8.0 \mathrm{~km}$ . Using the relationship $\mathrm{r}=(1.2 \mathrm{fm}) \mathrm{A} 1 / 3$ together with the mass of a neutron, $1.67 \times 10^{-27} \mathrm{~kg}$ , estimate the mass of a neutron star.

A) $0.65 \times 10^{30}\mathrm{~kg}$
B) $0.16 \times 10^{30}\mathrm{~kg}$
C) $1.5 \times 10^{30} \mathrm{~kg}$
D) $0.49 \times 10^{30}\mathrm{~kg}$