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: Pathology
1 year old child with abdominal mass with calcification,possiblities are -a) Neuroblastomab) Wilm's tumorc) Nephronophthsisd)  Pheochromocytoma 
Select and explain. 
A. ac, B. ab, C. ad, D. bc
B: ab
Answer: B: ab 
Explanation: Neuroblastomas are most common malignant tumours in infancy. Stippled calcification is quite common in the tumour. They present with abdominal mass.
Usual age for diagnose of Wilms tumour is 4 months to 6 yrs., median being 3 yrs. Most common presentation is painless abdominal mass. Calcification seen in 5-10% of cases.