D- a person who is deprived of water will have high circulating levels of antidiuretic hormone (adh). the tubular fluid/plasma (tf/p) osmolarity is 1.0 throughout the proximal tubule, regardless of adh status. in antidiuresis, tf/p osmolarity > 1.0 at site c because of equilibration of the tubular fluid with the large corticopapillary osmotic gradient. at site e, tf/p osmolarity > 1.0 because of water reabsorption out of the collecting ducts and equilibration with the corticopapillary gradient. at site d, the tubular fluid is diluted because nac1 is reabsorbed in the thick ascending limb without water, making tf/p osmolarity < 1.0.