<prompt> Toxin production by conjnebacterium diphtheriae is due to ?Chromosomal mutationPresence of plasmidLysogenic conversionTransformation  <response>: Ans. is c i.e., Lysogenic conversion . 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. 