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
Law under oath is not necessary for- 
Select and explain. 
A. Wound certificate, B. Medical certificate, C. postmortem certificate, D. Expert opinion expressed in a treatise
D: Expert opinion expressed in a treatise
Answer: D: Expert opinion expressed in a treatise 
Explanation: The oath is not necessary for an expert opinion expressed in a treatise.
The oath is, however, necessary in a wound certificate, a medical certificate, and a postmortem certificate.