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: Surgery
Earliest method of diagnosing pituitary tumour 
Select and explain. 
A. CT scan, B. Visual field chaing, C. Visual evoked potential, D. X-ray skull
A: CT scan
Answer: A: CT scan 
Explanation: Ans. is 'a' i.e., CT Scan