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
From vitreous humor, estimation of time since death is done by: WB 11; NEET 13 
Select and explain. 
A. K+- level, B. Na+ level, C. Glucose level, D. Urea level
A: K+- level
Answer: A: K+- level 
Explanation: Ans. K+- level