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
Widmark's formula is used to calculate the quantity of the following in the body after equilibrium between the blood and tissue is reached: 
Select and explain. 
A. Methyl alcohol, B. Nitrous oxide, C. Ethyl alcohol, D. Lithium carbonate
C: Ethyl alcohol
Answer: C: Ethyl alcohol 
Explanation: C i.e. Ethyl alcohol