This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Poisoning, Subject name: Anatomy
An arrow mark or bird foot mark on the centre of head suggest it is 
Select and explain. 
A. Pit viper, B. Saw scaled viper, C. King cobra, D. Krait
B: Saw scaled viper
Answer: B: Saw scaled viper 
Explanation: If the head is triangular and covered with small scales, it may be poisonous(viper). If there is an arrow mark or bird foot mark on the centre of the head, it is poisonous (saw scaled viper) Ref: FORENSIC MEDICINE AND TOXICOLOGY Dr PC IGNATIUS THIRD EDITION PAGE 511