<prompt> Incubation period of Diptheria is2 -6 days2 - 6 hours2 - 6 weeks2 - 6 months  <response>: The incubation period in diphtheria is commonly 3-4 days. In some cases sho as a day. In carriers, the incubation period may be very prolonged. Reference: Textbook of Microbiology; Anathanarayan and panickers; 10th edition; Page no: 240 