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
The best investigation for cardiac tamponade is: 
Select and explain. 
A. 2-D echocardiography, B. Real time echocardiography, C. Ultrasound, D. M-mode echocardiography
A: 2-D echocardiography
Answer: A: 2-D echocardiography 
Explanation: Ans. 2-D echocardiography