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
Commonest sarcoma in children is - 
Select and explain. 
A. Rhabdomyosarcoma, B. Lipoma, C. Angiosarcoma, D. Fibrosarcoma
A: Rhabdomyosarcoma
Answer: A: Rhabdomyosarcoma 
Explanation: Rhabdomyosarcoma

Commonest sarcoma in children is rhabdomyosarcoma.
It is a tumour of Primitive mesodermal origin.
The most common site is head and neck.
The genitourinary region is the second most common site.
Other sites are extremities and retroperitoneum