This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
Incubation period of pertussis is – 
Select and explain. 
A. 7 days, B. 7–14 days, C. 14–28 days, D. 28 days
B: 7–14 days
Answer: B: 7–14 days 
Explanation: Pertussis 
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.

B. pertussis infection
              ↓
Incubation period (1-2 weeks)
             ↓
Catarrhal stage (1-2 weeks)
             ↓
Paroxysmal stage (2-4 weeks)
            ↓
Convalescent stage (1-2 weeks but may last 1 to 3 months)
Remember

Catarrhal stage is the stage of maximum infectivity.
Maximum complications occur in Paroxysmal stage.