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 best test to detect iron deficiency anaemia in a community with Iwo prevalence of iron deficiency is - 
Select and explain. 
A. PCV, B. Serum iron, C. Serum ferritin, D. Iron binding capacity
C: Serum ferritin
Answer: C: Serum ferritin 
Explanation: None