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: Unknown
Hallmark feature shown in ECG is ? 
Select and explain. 
A. Prominent U wave, B. Inverted T wave, C. Bizarre QRS wave, D. Osborn J wave
D: Osborn J wave
Answer: D: Osborn J wave 
Explanation: None