This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology (Gram Positive Bacilli, Gram Negative Bacilli), Subject name: Microbiology
[{'content': "Positive Schick's test indicates that person is: \nSelect and explain. \nA. Immune to diphtheria, B. Hypersensitive to diptheria, C. Susceptible to diphtheria, D. Carrier of diptheria", 'role': 'user'}, {'content': "Answer: C \nExplanation: Positive Schick's test indicates that person is Susceptible to diphtheria. Schick test: Toxin-antitoxin neutralization test. Done on the people before staing immunization to identify susceptible individuals. Susceptible individuals develop erythema and induration on test arm following intradermal inoculation (0.2ml I/D MLD) of toxin. Vaccine is administered only to those susceptible people. Since now safer toxoid preparations are available, it is obsolete.", 'role': 'assistant'}]