Solution
= Solution
{c}
If $M^2<Q^2$, then
$$
r^2F=(r-M)^2+(Q^2-M^2)>0.
$$
There is no positive root and no horizon hiding $r=0$ in the extended <Reissner-Nordstrom spacetime>. Its <Kretschmann scalar> diverges there, so \b[$r=0$ is a <naked singularity>]. It is a timelike <curvature singularity>, as the normal to nearby $r=\text{constant}$ <hypersurfaces> has positive squared norm $g^{rr}=F$.