This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Radiology
A woman presenting with abrupt onset of "the worst headache of her life" Which is the best investigation? 
Select and explain. 
A. NCCT of the head, B. Vessel carotid Doppler, C. No imaging, D. MRI
A: NCCT of the head
Answer: A: NCCT of the head 
Explanation: Ans. a. NCCT of the HeadPatients with severe, sudden onset of a first-time headache accompanied by strong evidence for an underlying cause on history or physical examination should have a NCCT scan of the head to rule out any secondary causes.