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: Radiology
[{'content': 'A  19 year old boy underwent a trauma, he visits the clinic with swollen lip and fractured maxillary central incisors. The encircled area in radiograph shows: \nSelect and explain. \nA. Fragment of the fractured tooth, B. Calculus in the salivary duct, C. Irritational calcinosis of the lips, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]