Common indicator organisms of water pollution is

Answer: Option A

Common indicator organism of water pollution is Escherichia coli.
Escherichia coli also known as E. coli is a Gram-negative, facultatively anaerobic, rod-shaped, coliform bacterium of the genus Escherichia that is commonly found in the lower intestine of warm-blooded organisms.
The bacteria, typically transmitted through contaminated food or drinking water, adheres to the intestinal lining, where it secretes either of two types of enterotoxins, leading to watery diarrhea.