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
Persistent diarrhoea in infants 
Select and explain. 
A. 7 days, B. 1 month, C. 21 days, D. 14 days
D: 14 days
Answer: D: 14 days 
Explanation: None