Which Statement Is Not True About the Resident Microbiota of the Respiratory

Which statement is not true about the resident microbiota of the respiratory tract?

A) Microbiota are only found in the upper respiratory tract.
B) The lungs have recently been found to contain a resident microbiome that resembles that found in the mouth.
C) Smoking affects the numbers and types of species in the microbiota.
D) Resident microbiota secrete antimicrobial peptides and compete with pathogens.
E) The resident microbiota of a healthy person is limited to just a few species of bacteria.