Which of the following set of elements can be detected using sodium fusion extract ?

By sodium fusion extract we can detect sulphur, nitrogen, phosphorus and halogens. The elements present in the compound are converted from covalent into ionic form by fusing the compound with sodium metal.

$$\begin{gathered} \mathrm{Na}+\mathrm{C}+\mathrm{N}\stackrel{\mathrm{\Delta }}{\to }\mathrm{NaCN} \\ 2\mathrm{Na}+\mathrm{S}\stackrel{\mathrm{\Delta }}{\to }{\mathrm{Na}}_2\mathrm{S} \\ \mathrm{Na}+\mathrm{X}\stackrel{\mathrm{\Delta }}{\to }\mathrm{NaX}(\mathrm{X}=\mathrm{Cl},\mathrm{Br}.\mathrm{I}) \\ 3\mathrm{Na}+\mathrm{P}{{\mathrm{O}}_4}^{-3}\to {\mathrm{Na}}_3{\mathrm{PO}}_4 \end{gathered}$$