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: Physiology
The normal range of serum osmolality (in mOsm/L): 
Select and explain. 
A. 270 to 285, B. 300 to 320, C. 350 to 375, D. 200 to 250
A: 270 to 285
Answer: A: 270 to 285 
Explanation: Normal serum osmolality ranges from 270-285 mOsm/L while in neonates, serum values as low as 266 mOsm/kg . And normal urine osmolality ranges from 40-1400 mOsm/L. Ref: Harrison's Principles of Internal Medicine, 16th Edition, Page 252; Handbook of Fluid, Electrolyte, and Acid-Base Imbalances By Joyce LeFever Kee, Betty J. Paulanka, Carolee Polek, 2009, Page 8.