This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
True about diphtheria are all except: 
Select and explain. 
A. Incubation period-2 to 5 days, B. Chemoprophylaxis is done with rifampicin, C. Previously immunized asymptomatic household contacts should receive booster dose, D. Child with diphtheria is given antitoxin
B: Chemoprophylaxis is done with rifampicin
Answer: B: Chemoprophylaxis is done with rifampicin 
Explanation: Ans. B. Chemoprophylaxis is done with rifampicina. Erythromycin for 10-14 days is used for prophylaxis.b. A child with diphtheria is treated with anti-toxin as soon as possible.c. Equine derived Antitoxin: 20,000-1,00,000 units I/M or I/V. is used