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: Medicine
30 year old female comes with visual defects, breast engorgement and Amenorrhea. Investigation of choice is 
Select and explain. 
A. CT brain, B. Serum prolactin, C. Biopsy, D. Mr angiography
B: Serum prolactin
Answer: B: Serum prolactin 
Explanation: This is likely to be a case of pituitary adenoma. The most common pituitary adenoma causing the symptoms is prolactinoma.