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': 'Investigation of choice for diagnostic evaluation of hydrocephalus in one month old child : \nSelect and explain. \nA. X-ray skull, B. USG, C. CT, D. MRI', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Investigation of choice for hydrocephalus in infant is USG.', 'role': 'assistant'}]