The correct answer is the collecting duct.
The term neprhon refers to the cellular structures of the mammalian kidney which filtrate the blood and create the urine.
The collecting duct is a structural component of the nephron, which collects the urine formed by the nephrons and sends it to the renal pelvis and ureters. The anti-diuretic hormone increases the collecting duct's permeability to water, by increasing the transcytosis of water.