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: Forensic Medicine
Drugs acting directly on the uterus are using for criminal aboion. All of the following are drugs which increases uterine contraction, EXCEPT: 
Select and explain. 
A. Arsenic, B. Nux vomica, C. Ergotamine, D. Quinine
A: Arsenic
Answer: A: Arsenic 
Explanation: Drugs which increase uterine contraction: Ergot Hydrastis canadensis Quinine Lead Pituitary extract Decoctions of cotton root bark, nitrobenzol, picrotoxin, and strychnine (Nux vomica) Ref: The Essentials of Forensic Medicine and Toxicology by Dr. K. S. Narayan Reddy, 27th edition, Page 374.