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: Social & Preventive Medicine
A village affected with epidemic of cholera, what is the 1st step which should to be taken in village to decrease the death from cholera 
Select and explain. 
A. Cholera vaccination to all individuals, B. Safe water supply and sanitation, C. Primary Chemoprophylaxis, D. Treat everyone in the village’ with tetracycline
B: Safe water supply and sanitation
Answer: B: Safe water supply and sanitation 
Explanation: None