Choice A reason: Bilirubin is a yellow pigment that is produced from the breakdown of hemoglobin in red blood cells. It is normally excreted by the liver into bile and then eliminated by the intestines. However, when there is an obstruction of bile flow in the liver due to cirrhosis, bilirubin accumulates in the blood and tissues, causing jaundice.

Choice B reason: Lipofuscin is a brown pigment that is derived from the oxidation of lipids and proteins in the cells. It is also known as "wear and tear" pigment because it accumulates with aging and reflects the cumulative damage to the cells.

Choice C reason: Steatosis is a condition where fat accumulates in the cytoplasm of hepatocytes (liver cells). It can be caused by various factors, such as alcohol abuse, obesity, diabetes, or malnutrition.

Choice D reason: Phenylketonuria is a genetic disorder where phenylalanine, an amino acid, cannot be converted into tyrosine, another amino acid, due to a deficiency of an enzyme called phenylalanine hydroxylase. This leads to a buildup of phenylalanine and its metabolites in the blood and tissues, causing brain damage and mental retardation.