This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Heart, Circulation, and Blood, Subject name: Physiology
During intrauterine life, hepatic stage of erythropoiesis starts at? 
Select and explain. 
A. 2nd week, B. 5th week, C. 12th week, D. 18th week
C: 12th week
Answer: C: 12th week 
Explanation: Ans. C 12th weekRef: Diagnostic Pediatric Hematopathology By Maria A. Proytcheva 2011 ed. pg. 6Fetal liver is the major site for erythropoeisis between 11 and 24 weeks of gestation. Primitive hematopoiesisDefinitive hematopoiesisHematopoietic siteYolk sac and vascular endotheliumFetal liver and fetal bone narrow Hematopoietic nichesType of HematopoiesisMostly erythroidMultileneage HematopoiesisRBCCharacteristicsRemain Nucleated during their entire lifespanEnucleated RBCsCell SizeMacrocyticMCV decreases with gestational age Primitive hematopoiesisDefinitive hematopoiesisSensitivity to EPOIncreasedLower sensitivityLifespanShortIncreases with gestationHemoglobin typeEmbryonic: Gower 1, Gower 2 and PortlandFetal Hb (a2 y2 ) and adult Hb (a2 b2 )