This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood: RBCs, Anemia, and Polycythemia, Subject name: Physiology
[{'content': 'During second trimester of pregnancy, erythropoiesis occurs in the fetus primarily in? \nSelect and explain. \nA. Liver, B. Spleen, C. Red bone marrow, D. Lymph nodes', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) LiverSites of HaematopoiesisYolk sac at 2 weeksEarliest Hemoglobin to be formed isGower 1. This is followed by Gower 2 and finally Portland.In fetus in liver and partly spleen.HbF appears at 14 weeksAt birth it shifts to the bone marrowHbA appears at 38 weeksMISCELLANEOUS', 'role': 'assistant'}]