This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Medicine
Which is a immunological marker of type I diabetes? 
Select and explain. 
A. Anti-endothelial antibody, B. GAD, C. Anti-saccharomyces antibody, D. None of the above
B: GAD
Answer: B: GAD 
Explanation: Ans. B. GADImmunologic markers in type 1 DM:a. Islet cell autoantibodies (ICAs)b. Antibody to insulin (IAA)c. Glutamic acid decarboxylase, (GAD)d. Tyrosine phosphatase (IA-2 & IA- 2B)e. Beta cell specific zing transporter (ZnT - 8)