The correct option is C By ADH and regulation of blood volume
Urine is produced not only to eliminate many cellular waste products, but also to control both, the amount and the composition of the extracellular fluid in the body. When the blood becomes more concentrated, as happens when an animal is deprived of water, ADH is secreted and causes more water to be absorbed from the collecting ducts so that concentrated urine is produced. When plenty of water has been consumed and the blood is diluted, no ADH is secreted and no or little water is absorbed from the collecting ducts, so dilute urine is produced. In this way, the concentration and volume of the blood are controlled precisely.