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: Gynaecology & Obstetrics
Investigation of choice in hyperprolactinemia is which of the following? 
Select and explain. 
A. CT brain, B. MRI brain, C. Prolactin estimation, D. CH estimation
C: Prolactin estimation
Answer: C: Prolactin estimation 
Explanation: The diagnosis of hyperprolactinemia is made by estimation of fasting morning prolactin.