Because of Biochemical Oxygen Demand (BOD), Dissolved Oxygen (DO) of a water body:

Correct option is B

Biochemical Oxygen Demand (BOD) is a measure of the amount of oxygen required by microorganisms to decompose organic matter in water. When BOD levels are high, it indicates a high presence of organic matter, which increases the activity of bacteria that consume Dissolved Oxygen (DO). As these microorganisms break down organic matter, they use up DO, leading to a decrease in oxygen levels in the water.
Information Booster: · High BOD values indicate more organic pollution, which leads to increased microbial respiration and oxygen consumption, thus reducing DO levels in the water body.
· Lower DO levels can harm aquatic life, as organisms rely on oxygen for survival.