Read the following statements and choose the correct option.

Statement (A): Counter current mechanism helps to maintain a concentration gradient in the medullary interstitium of kidneys.

Statement (B): Interstitial gradient in medulla helps in an easy passage of water from the collecting tubule.

The counter-current mechanism is a crucial process in the kidneys that establishes a concentration gradient in the medullary interstitium. This gradient allows for the easy passage of water from the collecting tubules, facilitating the reabsorption of water and enabling the kidney to produce either concentrated or dilute urine, depending on the body's hydration needs.