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 objectives of tooth preparation are all except: \nSelect and explain. \nA. To conserve as much healthy tooth structure as possible, B. To remove all defects while providing protection  of  the  pulp–dentin  complex, C. To retain the defective, injured, or diseased  tooth form, D. To allow for the esthetic placement of a restorative material where indicated', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Tooth preparation is the mechanical alteration of a defective, injured, or diseased tooth such that placement of restorative material reestablishes normal form (and therefore function) including esthetic corrections, where indicated.\nGenerally, the objectives of tooth preparation are to\n\nConserve as much healthy tooth structure as possible.\nRemove all defects while simultaneously providing protection\xa0 of\xa0 the\xa0 pulp–dentin\xa0 complex.\nForm\xa0 the\xa0 tooth preparation so that, under the forces of mastication, the tooth or the restoration (or both) will not fracture and the restoration will not be displaced, and\nAllow for the esthetic placement of a restorative material where indicated.\n\nReference:\xa0 Sturdevant operative dentistry.\xa07th EDITION, Page No:120', 'role': 'assistant'}]