Given below are two statements: one is labelled as Assertion and the other is labelled as Reason. Assertion: Polluted water may have a value of BOD of the order of 17 ppm . Reason: BOD is a measure of oxygen required to oxidise both the biodegradable and non-biodegradable organic material in water. In the light of the above statements, choose the most appropriate answer from the options given below.

Step-by-step solution

The amount of oxygen required by bacteria to break down the organic matter present in a certain volume of a sample of water, is called Biochemical Oxygen Demand (BOD). The amount of BOD in the water is a measure of the amount of organic material in the water, in terms of how much oxygen will be required to break it down biologically. Clean water would have BOD value of less than 5   ppm whereas highly polluted water could have a BOD value of 17   ppm or more.