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: Dental
[{'content': 'Leser Trelat sign is associated with \nSelect and explain. \nA. CNS tumours, B. Lung cancer, C. Gastrointestinal tumors, D. Malignant melanoma', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]