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