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.

Atrial natriuretic peptide (ANP) is a hormone secreted by the heart when the atria are stretched by high blood pressure or volume.

ANP has multiple effects, such as increasing urine and salt excretion, lowering blood pressure, and opposing the renin-angiotensin-aldosterone system.
Therefore, ANP inhibits the release of renin and aldosterone, which are hormones that increase blood pressure and sodium retention.
Choice A is wrong because ANP is not released from the adrenal cortex but from the cardiac atria.
ANP does not stimulate atrial hormones but rather inhibits them.
Choice B is wrong because ANP is not stimulated to release when blood volume decreases, but when it increases.
ANP acts to reduce blood volume by promoting diuresis and natriuresis.
Choice C is wrong because ANP does not raise blood pressure, but lowers it. ANP acts as a vasodilator and reduces peripheral resistance.

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.