Which one of the following hormones, though synthesized elsewhere, is stored and released by the master gland?

Antidiuretic hormone is synthesized by the neurons of the hypothalamus and it is stored and released into the blood by the posterior lobe of the pituitary gland. It is also known as Vasopressin; it acts on the kidneys to control the amount of water excreted in the urine. Hence, option A is correct.