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
Which of the following statements is true about hapten? 
Select and explain. 
A. It induces brisk immune response, B. It needs carrier to induce immune response, C. It is a T-independent antigen, D. It has no association with MHC
B: It needs carrier to induce immune response
Answer: B: It needs carrier to induce immune response 
Explanation: Ans. is 'b' i.e., It needs carrier to induce immune response(Ref: Ananthanarayan, 9th/e, p. 87 and 8th/e, p. 91)* Haptens are small molecules that elicit an immune response only when attached to a large carrier such as a protein: the carrier may be one that also does not elicit an immune response by itself. (In general, only large molecules, infectious agents, or insoluble foreign matter can elicit an immune response in the body).