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
A child presents with respiratory distress. A vascular ring is suspected. Investigation of choice is - 
Select and explain. 
A. PET, B. CT, C. MRI, D. Angiography
C: MRI
Answer: C: MRI 
Explanation: Vascular rings are anomalies of the great vessels or their major branches which completely encircle the trachea and the esophagus in the superior mediastinum. MRI provides complete anatomical details of vascular rings.