This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Health Programmes in India, Subject name: Social & Preventive Medicine
A problem village is one wrhere - 
Select and explain. 
A. Source of water > 1[?]6 km away, B. Water available > 15 meters depth, C. Excess of fluoride in water, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Ans. is i.e., All of the above o A problem village has been defined as oneWhere no source of safe water is available within a distance of 1.6 km, or Where water is available at a depth of more than IS meters, orWhere water source has excess salinity, iron, fluorides and other toxic elements, orWhere water is exposed to the risk of cholera.