The correct relationship between theoretical oxygen demand (TOD) , biochemical oxygen demand(BOD) , chemical oxygen demand(COD) is given by:

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Detailed Solution:

Concept:

1- BOD, COD, TOC and TOD all are associated with organic content of water.

2- COD is related to both organic and inorganic content of water

3- COD is also known as Di- chromate demand

COD is the amount of oxygen required by the biodegradable and non biodegradable organic matter in waste water

BOD is the biological oxygen demand required by the biodegradable organic matter in water water

TOD the through chemical reaction equations the exact amount of oxygen is calculated