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: Medicine
[{'content': 'A 4 1/2- year-old girl always had to wear warm socks even is summer season. On physical examination, it was noticed that\nshe had high blood pressure and her femoral pulse was weak as compared to radial and carotid pulse, a chest radiograph\nshowed remarkable notching of ribs along with their lower borders. This was due to: \nSelect and explain. \nA. Coarctation of aorta, B. Femoral artery thrombosis, C. Raynaud’s disease, D. Takayasu’s arteritis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Cold extremities, high B.P. in upper extremity with marked diminution of pulsations and B.P. in the lower extremity is characteristic of Coarctation of Aorta. More facts about Coarctation of Aorta Most patients are asymptomatic.\n\nSymptomatic patients usually present with following features. Headache dizziness\n\n* Epistaxis* Cold extremities and weakness in legs * Claudication with exercise.\n* Hypertension in upper extremities with marked diminution of pulsation in lower extremities.\n\nMid-systolic or continuous murmur over the anterior part of the chest and back.\n\n* Enlarged and pulsatile collateral vessels in intercostal spaces anteriorly in the axilla or posteriorly in interscapular area.\n\nUpper extremity is more developed than the lower extremity.\n\n* Remember that the Cardiac output responds normally to exercise.\n* Most common site* of Coarctation of Aorta is just distal to the origin of the left subclavian artery.\n\nIf it arises above the subclavian artery, blood pressure elevation is evident only in the right arm.\nBicuspid aortic valve* is the most common abnormality associated with coarctation of Aorta.\n\nRadiography\n\nnotching of the inferior surface of ribs*\nindentation of the aorta at the site of coarctation and ‘3’ sign* on the para mediastinal shadow.\n\nComplications:\xa0\n\ncerebral aneurysm\nleft ventricular failure*\ninfective endocarditis', 'role': 'assistant'}]