The Most Common Cause of Community Acquired Pneumonia, Streptococcus Pneumoniae

The most common cause of community acquired pneumonia, Streptococcus pneumoniae, is spread by

A) the body's weakened immune system.
B) microscopic droplets of fluid from the lungs that spread when a person sneezes or coughs.
C) a failure to wash one's hands after shaking hands with a person who has been infected.
D) cigarette smoking by the patient who contracts the infection.