Farmer's reducer is:
Potassium sulfite + Sodium sulphate
Potassium ferricyanide + Sodium thiosulphate
Potassium sulfite + Sodium hydroxide
All of the above
Farmer's Reducer is composed of separate solutions of Potassium Ferricyanide and Sodium Thiosulfate (plain hypo). These are usually combined just before use or are used as a two bath treatment.