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
In penicillin allergy, penicillin acts as a: 
Select and explain. 
A. Hapten, B. Carrier, C. Super antigen, D. Toxin
A: Hapten
Answer: A: Hapten 
Explanation: None