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: Ophthalmology
[{'content': 'A wave in ERG is due to the activity of – \nSelect and explain. \nA. Pigmented epithelium, B. Rods and cones, C. Ganglion cell, D. Bipolar cell', 'role': 'user'}, {'content': "Answer: B \nExplanation: Waves in ERG are :\n\n\nNegative 'a' wave represent the activity in rods and cones.\nPositive 'b' wave arises in inner retinal layers.\nPositive 'c' wave is associated with the pigmentary epithelium.", 'role': 'assistant'}]