Which of the following are correct processes?

• A

  $\mathrm{Fe}+{\mathrm{Al}}_2{\mathrm{O}}_3âŸ\P 2\mathrm{Al}+{\mathrm{Fe}}_2{\mathrm{O}}_3$

• B

  ZnO + C → Zn+ CO

• C

  ${\mathrm{Cr}}_2{\mathrm{O}}_3+2\mathrm{Al}âŸ\P 2\mathrm{Cr}+{\mathrm{Al}}_2{\mathrm{O}}_3$

• D

  $2{\left[\mathrm{Ag}(\mathrm{CN}{)}_2\right]}^{\mathrm{Θ}}+\mathrm{Zn}âŸ\P 2\mathrm{Ag}+{\left[\mathrm{Zn}(\mathrm{CN}{)}_4\right]}^{2−}$