This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
AB blood group antigen are known as.....factor - 
Select and explain. 
A. Duffy, B. Landsteiner, C. Rhesus, D. Lutheran
B: Landsteiner
Answer: B: Landsteiner 
Explanation: The ABO blood group system is widely credited to have been discovered by the Austrian scientist Karl Landsteiner, who identified the O, A, and B blood types in 1900. Antigens were termed on his name Ref: Ananthanarayan & Panikers textbook of microbiology 9th edition pg.no. : 191