Refining

The correct option is (B): cathode.

1. Blister copper:
Blister copper is the impure copper obtained after smelting, containing about 98-99\% copper along with impurities like sulfur, iron, and other metals. 2. Poling process:
Poling is a method used to purify blister copper. In this process, blister copper is heated in a furnace with a wooden pole or a pole made of green wood. The pole introduces hydrogen gas, which reacts with the impurities in the copper to form volatile compounds, leaving behind nearly pure copper. 3. Other methods:
Electrolytic refining is another common purification method for copper, but it is not the process used for blister copper.
Zone refining is used for purifying semiconductors, not copper.