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': 'The long and less divergent walls of a cast restoration result in: \nSelect and explain. \nA. Increased tensile strength, B. Decreased tensile strength, C. Increased retention, D. Decreased retention', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The gingival-to-occlusal divergence of these preparation walls may range from 2 to 5 degrees per wall from the line of draw. If the vertical walls are unusually short, a maximum of 2 degrees occlusal divergence is desirable to increase retention potential. \nAs the occlusogingival height increases, the occlusal divergence should increase because lengthy preparations with minimal divergence (more parallel) may present difficulties during the seating and withdrawal of the restoration.\n\nSturdevant operative dentistry\xa0 7th Edition, Page No:120', 'role': 'assistant'}]