Which of the following is the best definition of "microbial antagonism"?

A) the presence of pathogens on the surface of the skin, which will invade the body through abrasions
B) the presence of normal microbiota that protect the body by competing with pathogens in a variety of ways to prevent pathogens from invading the body
C) the presence of normal microbiota that can become pathogens under certain conditions
D) the ability of microbiota to mutate into pathogens
E) the presence of resident bacteria on the surface of the body and in cavities that connect to the surface