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
Runt disease is ? 
Select and explain. 
A. Graft rejection, B. Graft vs host disease, C. Host vs graft disease, D. Type III hypersensitivity
B: Graft vs host disease
Answer: B: Graft vs host disease 
Explanation: Ans. is 'b' i.e., Graft vs host disease