The point of intersection and sudden increase in the slope, in the diagram given below, respectively, indicates:

$\Delta \mathrm{G}=0$ and melting or boiling point of the metal oxide

$\Delta \mathrm{G}>0$ and decomposition of the metal oxide

$\Delta \mathrm{G}<0$ and decomposition of the metal oxide

$\Delta \mathrm{G}=0$ and reduction of the metal oxide