Explanation:
\[\begin{array}{l}
{\rm{Molecule/ion}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\rm{Hybridisation}}\\
{\rm{NO}}_{\rm{3}}^ - \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\rm{s}}{{\rm{p}}^{\rm{2}}}\\
{\rm{BC}}{{\rm{l}}_{\rm{3}}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\rm{s}}{{\rm{p}}^{\rm{2}}}\\
{\rm{ClO}}_{\rm{2}}^ - \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\rm{s}}{{\rm{p}}^{\rm{3}}}\\
{\rm{Cl}}{{\rm{O}}_{\rm{3}}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\rm{s}}{{\rm{p}}^{\rm{3}}}\\
{\rm{So,the}}\,\,{\rm{correct}}\,\,{\rm{option}}\,{\rm{is}}\,{\rm{(1)}}{\rm{.}}
\end{array}\]