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
Toxin production by Corynebacterium diphtheria is due to ? 
Select and explain. 
A. Chromosomal mutation, B. Presence of plasmid, C. Lysogenic conversion, D. Transformation
C: Lysogenic conversion
Answer: C: Lysogenic conversion 
Explanation: Ans. is 'c' i.e., Lysogenic conversion o The toxigenicity of the diphtheria bacilli depends on the presence in it of corynephages (tox +). Nontoxigenic strains may be rendered toxigenic by infecting them with beta phage or some other larger phage. This is known as lysogenic conversion or phage conversion.