This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Toxicology - 2, Subject name: Forensic Medicine
[{'content': 'If the head of the snake has small scales covering the whole surface of the head it indicates \nSelect and explain. \nA. Viper, B. Cobra, C. Krait, D. Non venomous', 'role': 'user'}, {'content': 'Answer: A \nExplanation: All poisonous snakes have small head scales except cobra, krait & pit viper. These three snakes can be identified by 1. Pit viper: pit below the eye 2. Cobra: 3rd labial touches eye and nasal shields 3. Krait: 4 infralabial scales below mouth & 4th being largest Russel viper', 'role': 'assistant'}]