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': 'Medusa lock appearance in X-ray is seen in: \nSelect and explain. \nA. Ascariasis, B. Tapeworm, C. Hook worm, D. Ascaries and tapeworm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Ascariasis', 'role': 'assistant'}]