Very pure nitrogen can be obtained by:

Thermal decomposition of $\mathrm{Ba}{({\mathrm{N}}_3 )}_2$ is done as,

$\mathrm{Ba}{\left({\mathrm{N}}_3\right)}_2\to \mathrm{Ba}+3{\mathrm{N}}_2.$

thermal decomposition of ${\mathrm{NaN}}_3$ gives sodium and nitrogen.

Thus, options 1 and 2 are correct.