Which of the Following Statements Concerning the Loop of Henle

Multiple Choice

Which of the following statements concerning the loop of Henle of juxtamedullary nephrons is correct?

A) the ascending limb of the loop of Henle is freely permeable to H₂O and NaCl.
B) the filtrate is isotonic as it enters the loop of Henle, hypertonic at the tip of the loop, and hypotonic as it leaves the loop of Henle.
C) the descending limb of the loop of Henle actively transports NaCl out of the tubule into the interstitial fluid.
D) all of these answers.
E) none of these answers.