All of the Following Statements Are Correct About Microbial Colonization

All of the following statements are correct about microbial colonization of the human body EXCEPT:

A) The skin is a highly selective niche for certain microbes.
B) Oral microbiota can cause endocardiatis after dental surgery.
C) Cardiovascular normal flora are commensal species.
D) There are 1,000 times more anaerobes in the colon than aerobes.
E) Intestinal bacteria help modulate human mucosal immunity.