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
Cherry red spot at macula is seen in all of the following except: 
Select and explain. 
A. Tay-Sach's disease, B. Letterer-Siwe disease, C. Niemann-Pick disease, D. Commotio retinae
B: Letterer-Siwe disease
Answer: B: Letterer-Siwe disease 
Explanation: Ans. Letterer-Siwe disease