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': 'Anterior maxillary occlusal projection shows all of the following except: \nSelect and explain. \nA. Anterior maxilla, B. Teeth from 1st premolar to 1st premolar, C. Teeth from canine to canine, D. Anterior floor of the nasal fossa', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In anterior maxillary occlusal projection, the central ray is oriented through the tip of nose toward the middle of film with approximately +45 degrees vertical angulation and 0 degrees horizontal angulation.\nThe primary field of this projection includes the anterior maxilla and its dentition, as well as the anterior floor of the nasal fossa and teeth from canine to canine.', 'role': 'assistant'}]