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: Pathology
Response of iron therapy in a patient with iron deficiency anemia is denoted by: 
Select and explain. 
A. Restoration of enzymes, B. Reticulocytosis, C. Increase in iron binding capacity, D. Increase in hemoglobin
B: Reticulocytosis
Answer: B: Reticulocytosis 
Explanation: In uncomplicated cases, oral iron supplementation produces an increase in reticulocytosis in about 5-7 days that is followed by a steady increase in blood counts and normalization of red cell indices.