The usual incubation period of peusis is ?
Ans. is 'a' i.e., 7-14 days Whooping cough (peussis) After an incubation period of about 1-2 weeks, the disease takes a protracted course comprising three stages-- the catarrhal, paroxysmal and convalescent - each lasting approximately two weeks.
7-14 days
3-5 days
21-25 days
Less than 3 days