The correct answer is C. Join a study group of his peers
Step-by-step explanation:
During classes in some cases, students find difficulties in the process of understanding content. The first step to address this is to directly ask the teacher about it during class; however, if this does not help the student, he or she will need to try other methods to solve it. This includes trying to get a personal class with the same teacher or another teacher, try to learn about the topic of the class by yourself or looking for help in peers by joining or creating study groups.
According to this, the best option for Thayer is to join a study group of his peers because through a study group he can clarify concepts by discussing, and revising the content of the class. Also, his peers can explain to him aspects he does not understand, which might help him to understand better.