This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anatomy, Development and clinical examination, Subject name: Ophthalmology
A wave in ERG is due to the activity of 
Select and explain. 
A. Pigmented epithelium, B. Rods and cones, C. Ganglion cell, D. Bipolar cell
B: Rods and cones
Answer: B: Rods and cones 
Explanation: Normal record of ERG consists of the following waves : a-wave. It is a negative wave possibly arising from the rods and cones. b-wave. It is a large positive wave which is generated by Muller cells but represents the activity of the bipolar cells. c-wave. It is also a positive wave representing the metabolic activity of pigment epithelium. Both scotopic and photopic responses can be elicited in ERG. Foveal ERG can provide information about the macula. REFERENCE : AK KHURANA COMPREHENSIVE OPHTHALMOLOGY, Edition4,Page-489