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: Surgery
True about cystic hygroma 
Select and explain. 
A. Present in anterior triangle of neck, B. Sclerosing agents are not useful, C. Pre-operative MRI is crucial, D. Surgery is always indicated
C: Pre-operative MRI is crucial
Answer: C: Pre-operative MRI is crucial 
Explanation: None