Which Statement Concerning the Medullary Vertical Osmotic Gradient Is INCORRECT

Which statement concerning the medullary vertical osmotic gradient is INCORRECT?

A) The loops of Henle of juxtamedullary nephrons establish a medullary vertical osmotic gradient by means of countercurrent multiplication.
B) The vasa recta enable the medulla to be supplied with blood while conserving the medullary vertical osmotic gradient by means of countercurrent exchange.
C) The countercurrent system establishes and maintains a medullary vertical osmotic gradient ranging from 300 to 1,200 mosm/litre.
D) The collecting tubules of the juxtamedullary nephrons but not the cortical nephrons descend through the medullary vertical osmotic gradient before emptying into the renal pelvis.