Answer:
C. Encoding specificity
Explanation:
Encoding specificity is known to be a principle that explains that the memories of MAN are easily retrieved when the external conditions during the time of retrieval is exact duplicate of those that were in place when the memory was initially stored.
In this case, Beatrice was able to do better in exams when she studies in the classroom because , it was in the classroom that she received the lectures { where the memory was stored} .Therefore it will seems as if she is still receiving lectures when she studies in the classroom, and this will help her to remember what she was taught easily.