This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Adverse Drug Effect, Subject name: Pharmacology
Megaloblastic anemia is caused by - 
Select and explain. 
A. Phenytoin, B. Lithium, C. Lead, D. Chloroquine
A: Phenytoin
Answer: A: Phenytoin 
Explanation: Ans. is 'a' i.e., PhenytoinSome important drugs causing megaloblastic anaemiao Methotrexateo Phenytoino Cytosine arabinosideo Phenobarbitoneo Pentamidineo Pyrimethamineo Zidovudineo 5-Fluorouracilo Sulfasalazineo Triamtereneo Primidoneo Trimethoprimo Azathioprine