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': 'Which of the following chemical can cause contact leucoderma? \nSelect and explain. \nA. PTBP, B. DEC, C. Clofazimine, D. BACA', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Para tertiary butyl phenol (PTBP) is a adhesive used in sticker bindhi that can cause contact leucoderma.', 'role': 'assistant'}]