This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Corynebacterium, Subject name: Microbiology
[{'content': 'Clinical diphtheria is caused by: (PGI June 2009) \nSelect and explain. \nA. Corynebacterium diphtheriae, B. Corynebacterium parvum, C. C. Ulcerans, D. Streptococcus pyogens', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans: A (Corynebacterium . diph-theriae) "Diphtheria is a nasopharyngeal & skin infection caused by corynebacterium diphtheriaQ- H17th/890C. Ulcerans (H17th/893-95)# Cause exudative pharyngitis & cutaneous diseaseQ# Produce both diphtheria toxin & dermonecrotic toxinC. ulcerans infection is considered a zoonosis & person to person transmission has not been firmly establishedC. Pseudotuberctilosis (Preisz Nocard bacillusQ or C. Hofmannii)- H17th /894 & A 7th/240# Cause pseudotuberculosis\'\'in sheep & suppurative lymphadenitis in horses#Not produce diphtheria toxin#It is part of normal flora of nasopharynxHuman infections- particularly endocarditis of either prosthetic valve or native valves & invasive pneumonia- have been identified only rarelyCorynebacterium Parvum (A7th/240)It is used as immunomodulatorStrptococcus Pyogens (A7th/204)Causes upper respiratory tract infection, pyoderma, rheumatic fever & glomerulonephritis', 'role': 'assistant'}]