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The correct answer option is 4) All of the above

Lavigation:

It is also known as the hydraulic washing method and is applied to the purification of heavier ores like native gold, carbonates, oxides, etc. Running water is used to wash the ore, removing the lighter impurities while allowing the heavier ones to sink.

Froth floatation:

The principle of froth floatation is that sulphide ores are preferentially wetted by pine oil, whereas the gangue particles are wetted by water. Collectors are added to enhance the non-wettability of the mineral particles. 

Hand picking:

Ore can be concentrated traditionally by hand, just by picking it with the hands. This process involves using a hammer to separate the ore from the gangue, or adhering rocky elements.