This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Liver, Subject name: Pathology
Unconjugated hyperbilirubinemia is seen in - 
Select and explain. 
A. Rotor syndrome, B. Dubin-Johnson syndrome, C. Gilbert syndrome, D. Bile duct obstruction
C: Gilbert syndrome
Answer: C: Gilbert syndrome 
Explanation: Ans. is 'c' i.e., Gilbert syndrome {Ref: Harrison 18th/e p. 325 fig (42.1), 326 table (42.1); 17th/ep. 263 t. (43.1)]Causes of isolated hyperbilirubinemiaIsolated Indirect hyperbilirubinemiaIsolated Direct hyperbilirubinemiaA) Inherited conditionsInherited conditionso Cirgler Najjar type I and IIo Dubin Jhonson syndromeo Gilbert's syndromeo Rotors syndromeB) Ineffective ervthropoiesis Cobalamine folate, thalassemia, and severe iron deficiencies C) Drugs Rifampicin, Probenecid, Ribavarin D) Hemolytic disorder 1) Inherited o Spherocytosis, Elliptocytosis Glucose 6 phosphate dehydrogenase Pyruvate kinase deficiency o Sickle cell anemia 2) Acquired o Microangiopathic hemolytic anemia o Paroxysmal nocturnal hemoglobinuria o Immune hemolysis Unconiugated Bilirubin (Indirect bilirubin)o Isolated elevation o f unconjugated Bilirubin is rarely due to liver disease.o An isloated elevation of unconjugated Bilirubin is seen primarily in hemolytic disorders and in number of genetic conditions such as Crigter Najar and Gilbert's syndrome.Conjugated Bilirubin (Direct bilirubin)o In contrast to unconjugated bilinibinemia, conjugated bilirubinemia almost always implies liver or biliary tract disease.o Elevation of conjugated bilirubin may be seen in any type of liver disease. In most of the liver diseases both conjugated and unconjugated fraction of the bilirubin may be elevated.