Which of the following is a “pull” factor? a. political freedom c. racial discrimination b. political persecution d. overpopulation torn between b and d.

I would say political freedom as a pull factor. 
A push factor is a negative condition that would cause someone to leave their country. Racial discrimination, political persecution, and overpopulation are all reasons to leave your home. 
A pull factor is a positive condition that would cause someone to come to another country. The promise of political freedom is a reason to come to a place. 

a. political freedom