The correct option is D Diphtheria, leprosy, plague
Diseases caused by bacteria are bacterial diseases. Diphtheria is an upper respiratory tract illness caused by Corynebacterium diphtheriae, a facultative anaerobic, gram-positive bacterium. It is characterized by sore throat, low fever, and an adherent membrane (a pseudomembrane) on the tonsils, pharynx, and / or nasal cavity. Leprosy is a communicable bacterial disease caused by Mycobacterium leprae. Plague is a deadly infectious disease that is caused by the enterobacteria, Yersinia pestis. Option D is the only option in which the whole set consist of bacterial diseases.