Which of the following is  correct w.r.t. dipole-dipole interaction?

It is between molecules which have permanent dipoles.

Dipole-dipole interaction energy between stationary polar molecules (in solids) is inversely proportional to ${\mathrm{r}}^3$ (r is distance between two diples).

The partial charge is shown as $\mathrm{\delta }+ \mathrm{or} \mathrm{\delta }-.$

The charge on ends of dipoles possess “partial charges” less than that of unit electronic charge $1.6\times {10}^{-19}\mathrm{C}.$