Small amounts of urea enter the ___________ (K) of ___________ (J) which is transported back to the interstitium by the _________________ (L). The above described transport of substances facilitated by the special arrangement of Henle’s loop and vasa recta is called the counter current mechanism that helps to maintain a concentration gradient in the _________________ (C). Presence of such interstitial gradient helps in an easy passage of water from the _______________ (L).

Question

( a ) thin segment of the descending limb of Henle’s loop, collecting tubule; outer medullary interstitium; collecting tubule
( b ) thin segment of the ascending limb of Henle’s loop, collecting tubule; inner medullary interstitium; collecting tubule
( c ) thin segment of the ascending limb of Henle’s loop, collecting tubule; inner medullary interstitium; vasa recta
( d ) thick segment of the descending limb of Henle’s loop, collecting tubule; outer medullary interstitium; vasa recta