Given the correct sequence of Iron Deficiency Anaemia (IDA).
1. Fall in serum ferritin level.
2. Decrease in sustainable iron in bone marrow.
3. Fall in hemoglobin level.
4. Exhaustion of body iron reserves.

A. 1, 2, 3 and 4

B. 4, 2, 1 and 3

C. 2, 3, 4 and 1

D. 3, 4, 2 and 1

Answer: Option D