Identify the independent variable in the research scenario described below. 

Researchers want to know whether or not Fairness Training helps first-grade students share equipment more during recess. Researchers provide fairness training to three first-grade classes and then monitor students' activities during recess. 

This information is compared to three first-grade classes at a neighboring school that does not receive any fairness training before recess. 

What is the independent variable?

Select one:

a. Level of sharing at recess

b. Two different schools

c. Fairness Training

d. Recess