To solve this problem, we need to match the processes in Column I with their corresponding applications in Column II.$\newline$Let's analyze each process:$\newline$(a) Cyanide process:$\newline$• This process is used for the extraction of gold (Au).$\newline$• Gold is leached from its ore using a cyanide solution, forming a soluble gold-cyanide complex.$\newline$• Therefore, (a) matches with (iv) Extraction of Au.$\newline$(b) Froth flotation process:$\newline$• This process is used for the dressing of sulfide ores, such as ZnS (zinc sulfide).$\newline$• It involves the separation of hydrophobic materials from hydrophilic ones.$\newline$• Therefore, (b) matches with (ii) Dressing of ZnS.$\newline$(c) Electrolytic reduction:$\newline$• This process is used for the extraction of metals from their ores, such as aluminum (Al).$\newline$• In the Hall-Héroult process, alumina is electrolytically reduced to aluminum.$\newline$• Therefore, (c) matches with (iii) Extraction of Al.$\newline$(d) Zone refining:$\newline$• This process is used for obtaining ultrapure metals, such as germanium (Ge).$\newline$• It involves melting a small region of a solid and moving it along the solid to purify it.$\newline$• Therefore, (d) matches with (i) Ultrapure Ge.$\newline$Based on the analysis, the correct matching is:$\newline$Option 1: (a)->(iv), (b)->(ii), (c)->(iii), (d)->(i).