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: Radiology
Pleural effusion can be detected clinically when the amount of fluid is more than: March 2004 
Select and explain. 
A. 200 ml, B. 300 ml, C. 400 ml, D. 500 ml
D: 500 ml
Answer: D: 500 ml 
Explanation: Ans. D i.e. 500 ml