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: Pathology
[{'content': "Which one of the following is a metric dental feature? \nSelect and explain. \nA. Shovelling, B. Caravelli's trait, C. Mandibular molar groove pattern, D. Root length of maxillary canine", 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]