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: Forensic Medicine
Active ingredient of marking nut is - 
Select and explain. 
A. Semecarpol, B. Crotin, C. Abrin, D. None
A: Semecarpol
Answer: A: Semecarpol 
Explanation: Marking Nut Botanical name: Semicarpus anacardium Common name: Marking nut, bhilawa, biba Toxic Principle * Semecarpol * Bhilawanol REF;THE SYNOPSIS OF FORENSIC MEDICINE:KS NARAYANA REDDY;28th EDITION;PAGE NO317