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: Medicine
The pathogenesis of hypochromic anemia in lead poisoning is due to 
Select and explain. 
A. Inhibition of enzymes involved in heme biosynthesis, B. Binding of lead to transferrin, inhibiting the transport of iron, C. Binding of lead to cell membrane of erythroid precursors, D. Binding of lead to ferritin inhibiting their breakdown into hemosiderin
A: Inhibition of enzymes involved in heme biosynthesis
Answer: A: Inhibition of enzymes involved in heme biosynthesis 
Explanation: Lead interferes with the synthesis of Heme. Deficiency of heme causes microcytic hypochromic anemia because heme is an integral part of hemoglobin and it is well known that hemoglobin deficiency causes microcytic hypochromic anaemia.