system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Lt border of the heart in CXR is formed by – a) Pulmonary arteryb) Pulmonary  veinc) Abdominal aortad) Arch of aortae) Rt ventricles
assistant
The correct answer is  The left margin of heart is formed by aortic knuckle (prominence due to aortic arch), pulmonary trunk, left auricle, and left ventricle.