Answer:
I got a C because I don't have the aptitude for subjects from basic sciences, like chemistry. I usually perform better in social science related subjects.
Step-by-step explanation:
The student has a B+ average, which means his grades usually tend to A or B and an ocasional C, he might have more trouble on certain subjects related with basic sciences, such as chemistry or physics, and may perform very well in social sciences, such as history or English. The subjects in which he shows more aptitude help him increase his average.