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
Leptocytosis is seen in : 
Select and explain. 
A. Iron deficiency, B. Thalassaemia, C. Chronic liver disease, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Leptocytosis is the presence of unusually thin red cells. Leptocytes are seen in severe iron deficiency and thalassaemia. Target cell is a form of leptocyte in which there is central round stained area and a peripheral rim of haemoglobin. Target cells are found in iron deficiency, thalassaemia, chronic liver disease, and after splenectomy.