What system does the kidney disease affect

The right answer is: it affects the excretory function of the organism.

Take the example of chronic kidney disease (CKD).

Each minute, about 1 liter of blood is filtered by the kidney (1/5 of the amount pumped by the heart). Chronic kidney disease (or chronic renal failure) is a serious condition that causes a gradual and irreversible deterioration of the kidneys' ability to filter blood and excrete certain hormones. The excess of water and the waste metabolism products pass less into the urine and accumulate in the body.

c is the answer. hope this