You should consider a person's
a. Grade in the class
b. Personality
before asking them to join your study group.
c. All of these
d. None of these

C. All of these

Explanation:

Grades are obvious but personality is equally important. You should be able to get along in the study group. People could have different approaches to learning than your comfortable with or arguments over how to set up/how to do things can become a distraction to spending time understanding material.

no its not a run on sentence however i think you meant wet suits not sours also a run on sentence would be like surfers surf all winter long in southern california by using wet sours to keep them warm and the live their all year long