This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: AIIMS 2019, Subject name: Pathology
Which of the following finding are there in iron deficiency anemia? 
Select and explain. 
A. | TIBC, | Ferritin, | Transferrin saturation, B. | TIBC, | Ferritin, | Transferrin saturation, C. | TIBC, | Ferritin, | Transferrin saturation, D. | TIBC, | Ferritin, | Transferrin saturation
A: | TIBC, | Ferritin, | Transferrin saturation
Answer: A: | TIBC, | Ferritin, | Transferrin saturation 
Explanation: The diagnosis of iron deficiency anemia ultimately rests on laboratory studies. The serum iron and ferritin are low, and the total plasma iron-binding capacity (reflecting elevated transferrin levels) is high. Low serum iron with increased ironbinding capacity results in a reduction of transferrin saturation to below 15%. Reduced iron stores inhibit hepcidin synthesis, and its serum levels fall.