Correct Answer: albumin

Solution : The correct option is - albumin.

Albumin is a type of protein that is naturally found in the blood. It plays several crucial roles in the body, including maintaining the osmotic pressure of blood and transporting various substances. Normally, albumin is too large to pass through the filtration process in the kidneys and, therefore, it is not present in significant amounts in urine. However, in certain medical conditions, such as kidney disease, the glomerular filtration barrier in the kidneys may become damaged or compromised. This can lead to the leakage of albumin from the blood into the urine, a condition known as albuminuria or proteinuria.