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
Upper reference curve in growth cha is: 
Select and explain. 
A. 50th percentile, B. 60th percentile, C. 70th percentile, D. 80th percentile
A: 50th percentile
Answer: A: 50th percentile 
Explanation: 50th percentile