Which of the following statements about the three regions of the Loop of Henle is true?
a, Active transport of sodium and chloride ions occurs in the descending limb
b. Active transport of sodium and chloride ions occurs in the thin ascending limb
c. The thin ascending limb is impermeable to water but highly permeable to sodium and chloride ions.
d. The descending limb is impermeable to water but highly permeable to sodium and chloride ions.