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': 'Delta sign on CT head is seen in: \nSelect and explain. \nA. Infarct, B. Superior saggital sinus thrombosis, C. SAH, D. EDH', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. Superior saggital sinus thrombosis', 'role': 'assistant'}]