This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
Cholera prophylaxis is by - 
Select and explain. 
A. Doxycycline 300mg OD, B. Cephalosporin, C. Streptomycin, D. Cotrimoxazole
A: Doxycycline 300mg OD
Answer: A: Doxycycline 300mg OD 
Explanation: A single oral dose of doxycycline (300mg for adults and 6mg/kg for children under 15 years) has proved to be effective for chemoprophylaxis of cholera. Ref: PARK&;S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE 23rd edition , Page 233