Final answer:
Atrial Natriuretic Factor (ANF) is the hormone that lowers the blood pressure to the kidneys by promoting excretion of Na+ and water, which leads to a reduction in blood volume.
Step-by-step explanation:
Among the hormones listed, the one that would lower the blood pressure to the kidneys is Atrial Natriuretic Factor (ANF) or Atrial Natriuretic Peptide (ANP). This hormone acts as a vasodilator and is released by the cells in the atrium of the heart in response to high blood pressure. It prevents sodium reabsorption by the renal tubules, thereby decreasing water reabsorption, and promotes the excretion of Na+ and water. This has a diuretic effect which leads to a decrease in blood volume and consequently lowers blood pressure. In contrast, aldosterone and ADH (anti-diuretic hormone) lead to increased water retention and an increase in blood pressure, while estrogen has a variable effect on water and sodium balance and is not directly associated with lowering blood pressure. Therefore, ANF is the hormone that directly lowers blood pressure by increasing urinary output and reducing blood volume.