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
Moderately hard water has hardness level 
Select and explain. 
A. <1, B. 3-Jan, C. 6-Mar, D. >6
B: 3-Jan
Answer: B: 3-Jan 
Explanation: Ref: 25th Ed K.Park's Textbook Of Preventive and Social Medicine Pgno : 763