Select the correct statement(s):

Below this temperature the free energy of the formation of the oxide is negative, so the oxide is stable. Above this temperature the free of formation of the oxide is positive, and the oxide becomes unstable and should decompose into the metal and dioxygen. And all oxides can be decomposed to give the metal and dioxygen if a sufficiently high temperature can be attained.

Ellingham diagram us a plot between  $\Delta G^0$ and $T$

The metal oxide ($M_{x}O$) is stable at a point in a curve below which △G is negative. Above this point, the metal oxide is unstable. Hence option D is incorrect.

 Options A, B and C are correct.