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: Microbiology
Positive Schick test indicates that the person is: 
Select and explain. 
A. Immune to diphtheria, B. Hypersensitive to diphtheria, C. Susceptible to diphtheria, D. Susceptible and hypersensitive to diphtheria
C: Susceptible to diphtheria
Answer: C: Susceptible to diphtheria 
Explanation: Positive Schick reaction: 
This is characterized by a local inflammatory reaction that reaches maximum intensity in 4–7 days in the test arm and then reduces gradually. This indicates the absence of an immunity to C.diphtheriae.
Parija SC. Textbook of Microbiology & Immunology. Elsevier Health Sciences; 2014. Page:219