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': 'Fins and spines on the casting is seen due to \nSelect and explain. \nA. Prolonged heating, B. Rapid heating rate, C. Water film contamination, D. Too high pressure during casting', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]