This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Central Nervous system, Subject name: Pharmacology
Most teratogenic in pregnancy 
Select and explain. 
A. Phenytoin, B. Valproate, C. Barbiturate, D. Ethosuximide
B: Valproate
Answer: B: Valproate 
Explanation: Valproate is the most teratogenic, phenytoin also isn't safe. Phenobarbitone, lamotrigine, topiramate are relatively safe drugs but 4mg folic acid is required per day. Ref: KD Tripathi 8th ed.