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: Unknown
[{'content': 'Investigation of choice for acute appendicitis in children ? \nSelect and explain. \nA. USG, B. MRI, C. CT scan, D. X-ray', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans-A', 'role': 'assistant'}]