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: Ophthalmology
Spring catarrah is: 
Select and explain. 
A. Type I hypersensitivity reaction, B. Type II, C. Type III, D. Type IV
A: Type I hypersensitivity reaction
Answer: A: Type I hypersensitivity reaction 
Explanation: Ans. Type I hypersensitivity reaction