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: Pharmacology
What is the formula for parenteral iron therapy? 
Select and explain. 
A. 4.4 body weight (kg) Hb deficit (g/dl), B. 3.3 body weight (kg) Hb deficit (g/dl), C. 2.2 body weight (kg) Hb deficit (g/dl), D. 1.1 body weight (kg) Hb deficit (g/dl)
A: 4.4 body weight (kg) Hb deficit (g/dl)
Answer: A: 4.4 body weight (kg) Hb deficit (g/dl) 
Explanation: Ans. is 'a' i.e., 4.4 body weight (kg) Hb deficit (g/dl) Total parenteral iron requirement can be calculated by :? 4.3 x Body weight (kg) x Hb deficit (g/dl)