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: Radiology
[{'content': 'Biconvex hyperdense shadow on non-contrast CT scan is seen in: \nSelect and explain. \nA. Extradural haemorrhage, B. Subdural haemorrhage, C. Subarachnoid haemorrhage, D. Intraventricular haemorrhage', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Extradural haemorrhage', 'role': 'assistant'}]