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': 'Residual ridge resorption is: \nSelect and explain. \nA. Directly proportional to the anatomic factor., B. Indirectly proportional to the force., C. Directly proportional to the damping effect., D. Directly proportional to the bone-forming factors.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]