This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
A 30 year old women pretests a history of amenorrhoea and impaired vision of six month' duration. Physical examination shows everything except for pale optic discs and diminished visual acuity. The most likely diagnosis is - 
Select and explain. 
A. Pituitary adenoma, B. Craniopharyngioma, C. Hypothalamic glioma, D. Benign intracranial hypeension
A: Pituitary adenoma
Answer: A: Pituitary adenoma 
Explanation: pituitary adenoma inhibits GnRH causes imbalance in FSH and LH causing amenorrhea and increased ICT causes compression of optic disc & visual field defects ( harrison 17 2205 )