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
Two litres of normal saline in 4 hours will stimulate secretion of- 
Select and explain. 
A. Atrial natriuretic peptide, B. IL-2, C. TNF - alpha, D. Prostaglandins
A: Atrial natriuretic peptide
Answer: A: Atrial natriuretic peptide 
Explanation: hyperosmolality occurs and blood volume increase causing atrial distention stimulating atrial natriuretic peptide ( Harrison 17 pg 1760)