This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epilepsy, Subject name: Pharmacology
A 30 year old female epileptic on phenytoin, developed weakness and fatigue. Blood examination revealed Hb = 4.6 gm. MCV = 102 fl and MCH = 40 pg/dl. What is the most probable diagnosis 
Select and explain. 
A. Heart failure, B. Iron deficiency anemia, C. Phenytoin induced agranulocytosis, D. Megalobalstic anemia.
D: Megalobalstic anemia.
Answer: D: Megalobalstic anemia. 
Explanation: Ans. is 'd' i.e. Megaloblastic anaemiaNormal valuesMCU- 86 - 98 fLMCH- 28 - 33 pg/cellHb (female) - 12-16 gm/dLLab finding in this pt. go in favour of megaloblastic anemia. H/O phenytoin intake is also suggestive of same.