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': 'Investment breakdown or air bubbles on wax can affect the casting, as: \nSelect and explain. \nA. Leads to the surface roughness of casting., B. Fins on casting., C. Distorted casting., D. Microporosity.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]