This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
[{'content': "Bart's hydrops fetalis is lethal because – \nSelect and explain. \nA. Hb Bart's cannot bind oxygen, B. The excess a – globin form insoluble precipitates, C. Hb Bart's cannot release oxygen to fetal tissues, D. Microcytic red cells become trapped in the placental", 'role': 'user'}, {'content': "Answer: C \nExplanation: `In the foetus excess, gamma globin chains form tetramers (1Ib Barts) with such high affinity for oxygen that they deliver almost no oxygen to tissues' - Robbins\n\nClinically this condition manifests as hydrops fetalis and fetus shows features similar to those of erythroblastosis fetalis → Severe pallor, Generalized edema, Massive hepatosplenomegaly", 'role': 'assistant'}]