This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Pathology
[{'content': 'The quantity of globin chain synthesis is reduced in \nSelect and explain. \nA. HbS, B. Thalassemia, C. HbC, D. HbF', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Heme Synthesis. Heme is synthesized in a complex series of steps involving enzymes in the mitochondrion and in the cytosol of the cell (Figure 1). The first step in hemesynthesis takes place in the mitochondrion, with the condensation of succinyl CoA and glycine by ALA synthase to form 5-aminolevulic acid (ALA) Ref Robbins 9/e pg 413', 'role': 'assistant'}]