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: Dental
In National Water Supply and Sanitation programme a problem village is defined as all except? 
Select and explain. 
A. Distance of safe water is greater than 1.6 Km, B. Water is exposed to the risk of cholera, C. Water source has excess iron and heavy metals, D. Water infested with Guniea worm
D: Water infested with Guniea worm
Answer: D: Water infested with Guniea worm 
Explanation: None