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
Process of dark adaptation involves: 
Select and explain. 
A. Rods of retina, B. Cones of retina, C. Pigment epithelium of retina, D. Both rods and cones
D: Both rods and cones
Answer: D: Both rods and cones 
Explanation: Ans. Both rods and cones