What is the gravitational self energy of a solid sphere of mass M and radius R ?

Q: What is the gravitational self energy of a solid sphere of mass M and radius R ?

(a) $-\frac{3}{5} \frac{G M^2}{R}$

(b) $-\frac{2}{5} \frac{G M^2}{R}$

(c)  $-\frac{1}{5} \frac{G M^2}{R}$

(d)  $-\frac{4}{5} \frac{G M^2}{R}$