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: Pharmacology
Drug causing phacomelia? 
Select and explain. 
A. Phenytoin, B. Alcohol, C. Lithium, D. Thalidomide
D: Thalidomide
Answer: D: Thalidomide 
Explanation: Ans. is 'd' i.e., Thalidomide o Even a single dose of thalidomide administered early in pregnancy may result in severe teratogenic effect in the form of phacomelia.