A hormone is a secreted molecule that is carried in the bloodstream to where it acts on target cells that bear specific receptors for that hormone.

Kidney disease can cause hypertension by activating the renin-angiotensin mechanism.
This mechanism involves the release of renin from the kidneys, which stimulates the production of angiotensin II, a hormone that constricts blood vessels and increases blood pressure.
Choice A is wrong because kidney disease does not directly signal the brain stem to increase blood pressure.
The brain stem regulates blood pressure through the autonomic nervous system, which responds to various stimuli such as stress, pain, or emotions.
Choice C is wrong because kidney disease does not increase the release (excretion) of sodium and water.
On the contrary, kidney disease can impair the ability of the kidneys to filter out excess sodium and water, which can lead to fluid retention and increased blood pressure.
Choice D is wrong because kidney disease does not stimulate the secretion of ANP.
ANP stands for atrial natriuretic peptide, a hormone that is secreted by the heart when it senses high blood pressure.
ANP causes the kidneys to excrete more sodium and water, which lowers blood pressure.

Exocrine glands secrete through ducts or tubes to the body’s exterior.

For example, sweat glands, salivary glands, and liver are exocrine glands.
Choice A is wrong because exocrine glands do not only secrete salts, but also other substances such as enzymes, mucus, and sebum.
Choice B is wrong because exocrine glands do not secrete hormones at all.
Hormones are secreted by endocrine glands, which are ductless glands that release their products directly into the bloodstream.
Choice C is wrong because exocrine glands do not secrete into the bloodstream, but onto an epithelial surface such as the skin or the gastrointestinal tract.

Only endocrine glands secrete into the bloodstream.