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
The principle that states 'when any two objects come into contact, there is always a transfer of material from each object on the other' is called? 
Select and explain. 
A. Locard's principle, B. Quetelet's rule, C. McNauton's principle, D. Gettler's principle
A: Locard's principle
Answer: A: Locard's principle 
Explanation: When any two objects come into contact, there is always a transfer of material from each object on the other. This called Locard's exchange principle. Ref: The Essentials of Forensic Medicine & Toxicology Dr.K.S.Narayan Reddy, 29th Edition, Page 442