Answer :
The false statement about Rickettsia rickettsii is that D.pathogen is transmitted from one person to another ( like syphilis).
Rickettsia rickettsii, responsible for Rocky Mountain spotted fever, is an obligate intracellular parasite transmitted via tick bites, specifically by the Dermacentor tick species such as the American dog tick and the Rocky Mountain wood tick. The pathogen has a peptidoglycan cell wall with an outer membrane containing lipopolysaccharides. It avoids destruction by preventing the fusion of the endocytic vesicle to the lysosome within host cells.
However, it is incorrect to say that Rickettsia rickettsii is transmitted from person to person (like syphilis). Transmission occurs only through tick bites, making statement d the false statement among the given options.