Answer:
B. Not all coliforms are harmless and symbiotic with human beings and some may carry genes/proteins that can make them dangerous to humans; it is best to keep coliforms OUT of our drinking water, since it is difficult to identify which ones might be harmless and which ones might be harmful.
Step-by-step explanation:
Coliforms refer to a classification of bacteria which ferment lactose, such as E. coli. Thus, they are indicators of fecal contamination in water and food. Even though not all coliforms are dangerous, they may contain pathogens that spread diseases, like viruses, bacteria and parasites.