If they didn't exist there would be chaos.
You would be dead.
I would be dead.
Everyone killing them selves.
It's gonna be like the purge, people stealing, people killing.
There would be no laws, rules or regulations regarding the environment. Crimes would be committed, and there would be no punishment or rehabilitation.
Someone planted B. their seeds here.
You cannot use A or C because you don't know whether that someone is a male or a female.
B the first time you run across a piece of useful information