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
Carotid artery stenosis screening invivo choice is : 
Select and explain. 
A. USG, B. CT, C. MRI, D. Doppler
D: Doppler
Answer: D: Doppler 
Explanation: Color doppler ultrasonography is the screening method of choice (not simple USG : option a is incorrect).
Carotid angiography is the investigation of choice for diagnosis.