The rate of BOD exerted at any time is A. Directly proportional to BOD satisfied B. Directly proportional to BOD remaining C. Inversely proportional to BOD satisfied D. Inversely proportional to BOD remaining

The correct answer is: C. Inversely proportional to BOD satisfied

BOD, or biochemical oxygen demand, is a measure of the amount of oxygen that is used by microorganisms to break down organic matter in water. The rate of BOD exerted at any time is inversely proportional to the amount of BOD that has already been satisfied. This means that the more BOD that has already been satisfied, the slower the rate of BOD exertion will be.

Here is a more detailed explanation of each option:

• Option A: Directly proportional to BOD satisfied. This is incorrect because the rate of BOD exerted is inversely proportional to BOD satisfied, not directly proportional to it.
• Option B: Directly proportional to BOD remaining. This is incorrect because the rate of BOD exerted is inversely proportional to BOD satisfied, not directly proportional to BOD remaining.
• Option C: Inversely proportional to BOD satisfied. This is the correct answer because the rate of BOD exerted is inversely proportional to BOD satisfied.
• Option D: Inversely proportional to BOD remaining. This is incorrect because the rate of BOD exerted is inversely proportional to BOD satisfied, not inversely proportional to BOD remaining.