This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nose and PNS, Subject name: ENT
[{'content': 'Transillumination test was commonly performed to diagnose infection of: \nSelect and explain. \nA. Maxillary sinus, B. Frontal sinusitis, C. Sphenoid sinus, D. Both (a) and (b)', 'role': 'user'}, {'content': 'Answer: D \nExplanation: A bright light placed against the hard palate transilluminate maxillary sinus and provides information about the presence of pus, tumour or polyp in the sinus. Similarly, a small lighted bulb placed under the floor of frontal sinus in the superomedial angle of orbit transilluminate frontal sinus. Transillumination cannot be done in sphenoid sinus because of its location. This test is now superseded by better methods of testing.', 'role': 'assistant'}]