Which Condition or Process Would Not Contribute to Production of Highly

Which condition or process would not contribute to production of highly concentrated urine in mammals?

A) Osmolarity gradient within the kidney medulla
B) Active transport of sodium and chloride ions out of the proximal convoluted tubule
C) Active transport of sodium and chloride ions out of the segment of the loop of Henle in which tubular fluid is leaving the medulla
D) Action of ADH to increase permeability of collecting tubule to water
E) Loop of Henle's impermeability to water