Lysogenic conversion is seen in:

Ans. is 'a' i.e., C. diphtheriaeRef: - Jawetz latest e/p. 274The 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.C. diphtheriae does not need to be toxigenic to establish localized infection.