This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuro-Ophthalmology, Subject name: Ophthalmology
Waves present in electroretinogram are all EXCEPT: 
Select and explain. 
A. a wave, B. bwave, C. c wave, D. d wave
D: d wave
Answer: D: d wave 
Explanation: ANSWER: (D) d waveREF: Khurana 4th ed p. 489Electroretinogram is composed of:a wave : Rods and Conesb wave : Muller cellsc wave: Pigment epithelium