Final answer:
B.Legionella pneumophila. Legionella pneumophila is unlikely to be transmitted by airborne droplets and is mainly acquired through contaminated water. Streptococcus pneumoniae, Neisseria meningitidis, and Treponema pallidum can be transmitted through airborne droplets and cause diseases such as pneumonia, meningitis, and syphilis.
Step-by-step explanation:
The organism that is unlikely to be transmitted by airborne droplets is Legionella pneumophila. Legionella pneumophila is the bacterium that causes Legionnaires' disease and is typically contracted through contact with contaminated water, rather than through airborne droplets. Legionnaires' disease is not easily transmitted from person to person and is mainly acquired by inhaling the bacteria from water sources.
On the other hand, organisms such as Streptococcus pneumoniae, Neisseria meningitidis, and Treponema pallidum can be transmitted through airborne droplets. These organisms are responsible for diseases such as pneumonia, meningitis, and syphilis, respectively.