The correct option is D Dialysis
Kidney failure can occur due to multiple reasons like infections, injury or reduced blood flow to the kidney. This leads to accumulation of metabolic wastes in the body which can be very harmful to the body if not removed in time. An artificial method of removing the metabolic waste from the blood was perfected in 1943 by Wilhelm Kolff of Netherlands and it is known as Dialysis. Present day dialysers use a rotating drum to pump out the blood slowly from the artery. The blood then passes through a filtration unit that contains a washing fluid or dialysate separated from the blood by a semipermeable membrane. The metabolic wastes, salt and excess fluid present in the blood diffuses across the membrane into the dialysate while the blood cells, proteins and hormones etc., are retained due to their larger size. The cleaned blood is then pumped back into a vein.