Which statement is NOT true of the normal flora of a person?

A)The bacteria in the vagina create an alkaline pH that inhibits the growth of pathogens.
B)The colon has bacteria that produce vitamins, especially vitamin K.
C)The cilia of the nasal cavities sweep inhaled microorganisms to the pharynx.
D)The part of the small intestine with the smallest bacterial population is the duodenum.