This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: HAEM synth and porphyrias, Subject name: Biochemistry
[{'content': 'Rate limiting enzyme of Haem synthesis in erythroid tissue is: \nSelect and explain. \nA. PBG deaminase, B. Uroporphyrin II cosynthetase, C. ALA synthase I, D. ALA synthase II', 'role': 'user'}, {'content': 'Answer: D \nExplanation: RLE in Haem Synthesis is - ALA Synthase ALA Synthase I : Expressed throughout the body. (Rate limiting step in liver) ALA Synthase II: Expressed in erythroid tissues', 'role': 'assistant'}]