When ${\mathrm{MnO}}_2$ is fused with $\mathrm{KOH}$ and ${\mathrm{KNO}}_3,$ a coloured compounds is formed, the product and its colour is

When ${\mathrm{MnO}}_2$​ is fused with $\mathrm{KOH}$ and ${\mathrm{KNO}}_3$​ potassium manganate,  ${\mathrm{K}}_2{\mathrm{MnO}}_4$ which​ is green coloured.

${\mathrm{MnO}}_2+{\mathrm{KNO}}_3+2\mathrm{KOH}\stackrel{∆}{\to }{\mathrm{K}}_2{\mathrm{MnO}}_4\left(\mathrm{green}\right)+{\mathrm{KNO}}_2+{\mathrm{H}}_2\mathrm{O}$

Hence, correct option is: (A) ${\mathrm{K}}_2{\mathrm{MnO}}_4$, Green