This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax, Subject name: Anatomy
[{'content': 'After the pericardial sac has been opened anteriorly during surgery, by passing a surgical clamp through the transverse sinus, surgeons can stop/dive circulation of blood in \nSelect and explain. \nA. Superior an inferior vena cava, B. Aoa and pulmonary veins, C. Aoa and pulmonary trunk, D. SVC and pulmonary veins', 'role': 'user'}, {'content': "Answer: C \nExplanation: During surgery, a clamp is passed through the transverse sinus stops or dives the blood flow from the aoa and pulmonary trunk. Transverse pericardial sinus seperates the aerial end of the hea tube from the venous end. Aoa and pulmonary trunk lie anterior to the sinus and superior vena cava lies posterior to it. Therefore, during surgery, a clamp is passed through the transverse sinus stops or dives the blood flow from the aoa and pulmonary trunk. Ref: Gray's Anatomy 41st edition Pgno: 183", 'role': 'assistant'}]