Answer:
Option A. An average student who excels under the guidance of a teacher who tells him that he is smart is benefiting from self-fulfilling prophecy.
Step-by-step explanation:
"Self-fulfilling prophecy" is a psychological term used to define a belief or expectation that a person holds about a future even that manifests because the person believes in it and holds to it. When the teacher expresses to the student that he is a smart, the student starts to believe this as true fact about him, and he starts to excel at school because of this belief. He unconsciously worked towards being smart by affirming his belief amplifying every positive aspect of his intellect, and minimizing the negative ones.