BOD refers to :
The amount of the oxygen that would be consumed to oxidize all the inorganic matter in one liter of water
The amount of the oxygen that would be consumed if all the organic matter in one liter of water were oxidized by bacteria.
The amount of the oxygen that would be consumed if all the organic and inorganic matter in one liter of water were oxidized by bacteria.
The amount of the oxygen that would be produced if all the organic matter in one liter of water were oxidized by bacteria.
The amount of oxygen that can be consumed if all the organic matter in one liter of water has to be oxidised by bacteria and fungi.