This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory Radiology, Subject name: Radiology
[{'content': 'Which of the following is not a pa of left mediastinal border on a PA chest radiograph? \nSelect and explain. \nA. Aoic arch, B. Pulmonary trunk, C. Left ventricle, D. SVC', 'role': 'user'}, {'content': 'Answer: D \nExplanation: - The Left Hea Border on CXR is formed by Aoic Knuckle, Pulmonary aery, Left Auricle, and Left Ventricle. - The Right Hea Border on CXR is formed by Superior Vena cava, Rt Atrium and Inferior Venacava.', 'role': 'assistant'}]