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: Unknown
Widmark's formula is used for measurement of blood levels of: 
Select and explain. 
A. Benzodiazepines, B. Barbiturates, C. Alcohol, D. Tranquilizers
C: Alcohol
Answer: C: Alcohol 
Explanation: Widmark's a = p.r.c., a= wt of alcohol in gms in body, p= body wt in kg, c= conc. of alcohol in blood in gm/kg, r = constant (0.6 for men, 0.5 for women).
For Urine, formula is- a = 3,4p.r.q, where q is the conc. of alcohol in urine in mg/kg.