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 component of hydrocolloid can lead to fixed drug eruptions? \nSelect and explain. \nA. CaSO4, B. Phenolphthalein, C. Na fluorititanate, D. Magnesium oxide', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]