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: Medicine
All the following statements are true about pertussis except: 
Select and explain. 
A. SAR is > 90%, B. There is no Subclinical or Chronic Carrier state, C. Leucocytosis correlates with the severity of cough, D. Doc is erythromycin
C: Leucocytosis correlates with the severity of cough
Answer: C: Leucocytosis correlates with the severity of cough 
Explanation: Leucocytosis does not correlate with the severity of cough.