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 17ppm.
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.

We need to evaluate the Assertion and Reason about BOD (Biochemical Oxygen Demand).

Evaluating the Assertion:

BOD of clean water is typically around 1-5 ppm. Polluted water can have a BOD value of 17 ppm or higher, as it contains a large amount of organic matter that requires more oxygen for decomposition.

Therefore, the Assertion is true.

Evaluating the Reason:

BOD (Biochemical Oxygen Demand) is defined as the amount of oxygen required by bacteria to break down only the biodegradable organic matter in water. It does NOT measure the oxygen required for non-biodegradable organic material.

The Reason states that BOD measures oxygen required to oxidise both biodegradable and non-biodegradable organic material, which is incorrect.

Therefore, the Reason is false.

Conclusion:

Assertion is true but Reason is false.

The correct answer is Option C.