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
A freshly prepared oral rehydration solution should not be used after - 
Select and explain. 
A. 4 hrs, B. 6 hrs, C. 12 hrs, D. 24 hrs
D: 24 hrs
Answer: D: 24 hrs 
Explanation: None