Answer:
Option (A).
Step-by-step explanation:
Haptens may be defined as incomplete antigen that are not capable of inducing an immune response.
Hapten is a small molecule that reacts with specific antibody but only generates an immune response when these are conjugated with the carriers or proteins. Penicillin is a hapten and generates an immune response when conjugated with the carrier molecule.
Thus, the correct answer is option (A).