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 50 year old male patient complains of heaviness of face, headache and blocked nose. Patient gives a history of chronic sinusitis. Waters view X-ray was taken. The patient position in this X-ray is: \nSelect and explain. \nA. Canthomeatal line parallel to film, B. Canthomeatal line at 37o with film, C. Canthomeatal line at -30o with film, D. Canthomeatal line at 10o with film', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Waters view-\xa0\nThe image receptor is placed in front of the patient and perpendicular to the midsagittal plane. The patient’s head is tilted upward\xa0so\xa0that\xa0the\xa0canthomeatal\xa0line\xa0forms\xa0a\xa037-degree\xa0angle\xa0with\xa0the\xa0image receptor. If the patient’s mouth is open, the sphenoid sinus is seen superimposed over the palate.\nWhite and Pharoah, Oral radiology, ed 7th, pg-161', 'role': 'assistant'}]