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
When horse serum is injected intravenously in to a rabbit and again in to the skin two or three weeks later, what is the necrotising reaction that occurs at the site of the second injection? 
Select and explain. 
A. Atopy, B. Anaphylaxis, C. Arthus phenomenon, D. Serum sickness
C: Arthus phenomenon
Answer: C: Arthus phenomenon 
Explanation: None