Silver is refined by electrolytic refining. In this method, impure silver is made the anode, pure silver is the cathode, and silver nitrate solution acts as the electrolyte.
The examiner expects you to name the method (electrolytic refining) and may award the mark for the name alone, but briefly stating the anode/cathode/electrolyte shows understanding and secures the mark confidently. This applies to refining of any metal, including silver.