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: Radiology
An ideal imaging method for diagnosing hydro-cephalus in an infant is: 
Select and explain. 
A. Plain X-ray, B. CT scan, C. Ultrasound, D. MRI
C: Ultrasound
Answer: C: Ultrasound 
Explanation: Ans. Ultrasound