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
[{'content': "Widmark's formula helps in the measurement of the blood level of - \nSelect and explain. \nA. Cocaine, B. Alcohol, C. Barbiturates, D. Benzodiazepines", 'role': 'user'}, {'content': "Answer: B \nExplanation: The basis for calculating the approximate quantity of alcohol in the body, after equilibrium between the blood and\xa0the tissues has been reached, is expressed by the\xa0Widmark's formula\n\na = p.r.c.\na-Weight of alcohol in g in body\np- the weight of the body in kg\nc- concentration of alcohol in blood in g/kg\nr- a constant obtained by dividing the average concentration of alcohol in the body by the average concentration of\nalcohol in the blood (0.085 for men, 0.055 for women)\n\nFor urine, formula is- a=3/4 p.r.q., where q - concentration of alcohol in urine in mg/kg", 'role': 'assistant'}]