This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Retina, Subject name: Ophthalmology
[{'content': 'Investigation of choice for diagnosing macular edema:- \nSelect and explain. \nA. Biopsy, B. FA, C. Optical coherence tomography, D. ERG', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Optical Coherence Tomography Non-excisional "OPTICAL BIOPSY" Uses low coherence interferometry, employs michelson interferometer 830 nm infrared light, Super luminescent diode light source. Not very specific in hazy media and myopic discs', 'role': 'assistant'}]