This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitreous and retina, Subject name: Ophthalmology
Marcus-Gunn sign is seen in - 
Select and explain. 
A. Retinitis pigmentosa, B. Retinal detachment, C. Diabetic retinopathy, D. Hypeensive retinopathy
B: Retinal detachment
Answer: B: Retinal detachment 
Explanation: causes of Marcus Gunn pupil. (In swinging flashlight test, the pupil on the diseasedside dilates on transferring light to it)  Optic neuritis  Optic atrophy  Retinal detachment  Central retinal aery occlusion  Central retinal vein occlusion Ref Comprehensive ophthalmology AK Khurana 4th edition page no 494