Thermal decomposition of which of the following yields nickel?

Which method of refining nickel is represented by the following equation?
$Ni$ (impure) $+ 4CO$ $\xrightarrow{320 \ K} Ni(CO)_4$ $\xrightarrow{420 \ K} Ni$ (pure) $+ 4CO$

Match the following:
| List-$I$ (Refining Methods) | List-$II$ (Metal to be refined) |
| :--- | :--- |
| $(A)$ Zone refining | $(I)$ Titanium |
| $(B)$ Poling | $(II)$ Tin |
| $(C)$ Liquation | $(III)$ Gallium |
| $(D)$ Vapour phase refining | $(IV)$ Copper |

Which of the following elements is purified by vapour phase refining?

Park's process is used in the extraction of

Name the process that is employed to refine aluminium.