This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and health, Subject name: Social & Preventive Medicine
Which of the following is considered an adequate water supply/head/day- 
Select and explain. 
A. 50-150L, B. 150-200L, C. 200-250L, D. 100-150L
B: 150-200L
Answer: B: 150-200L 
Explanation: park's textbook of preventive and social medicine 23rd edition *a daily supply of 150-200litres per capita is considered as an adequate supply to meet the needs for all urban domestic purposes .