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
Hardness of water has a beneficial which one of the following 
Select and explain. 
A. Renal diseases, B. Metabolic diseases, C. Cerebrovascular diseases, D. Cardiovascular diseases
D: Cardiovascular diseases
Answer: D: Cardiovascular diseases 
Explanation: "Hardness of water appears to have a beneficial effect against cardiovascular disease" - Park 621