Problem: In The Mount Sinai Regional Hospital group of physiologists started renal research. They are examining a 42-year-old man, who traveled alone and has no access to water for 36 hours. His urine osmolarity is 1100 mOsm/L. Which is primarily explained by the action of vasopressin on the:
A. Thin ascending limb of the loop of Henle
B. Early distal tubule
C. Medullary segment of the collecting duct
D.Cortical segment of the collecting duct
E. Juxtaglomerular apparatus