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
A 2 year old child presented with leukocoria in the right eye since 2 months. On examination a total retinal detachment was present in the same eye. Ultrasound B scan revealed a heterogenous sub retinal mass with calcification. The most likely clinical diagnosis is – 
Select and explain. 
A. Coats- disease, B. Retinoblastoma, C. Toxocariasis, D. Retinal tuberculoma
B: Retinoblastoma
Answer: B: Retinoblastoma 
Explanation: Leukocoria with calcification in subretinal mass suggests the diagnosis of exophytic retinoblastoma.
Exophytic retinoblastoma can cause retinal detachment.