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': 'Quartz is added to gypsum bonded investment to \nSelect and explain. \nA. Increase the strength, B. counter balance contraction of gypsum during heating, C. aid in hygroscopic expansion, D. increase the shelf life of investment', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]