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
Most sensitive and specific investigation for screening of Renovascular hypertension – 
Select and explain. 
A. MRI, B. Captopril enhanced radionuclide scan, C. Spiral CT Scan, D. Duplex – Doppler flow study
C: Spiral CT Scan
Answer: C: Spiral CT Scan 
Explanation: None