Justin plays for his high-school soccer team. he practices scoring touchdowns every day. during matches against other schools, he manages to score an average of three out of every five touchdowns he attempts. in this context, justin gets

Based on the description, in this context, justin gets a Partial reinforcements

Partial reinforcements are every factors that influence a person's behavior that only reinforced at a certain intervals of time.
Justin plays soccer, which has nothing to do with scoring touchdown. So, Justin practice how to score a touchdown only at a certain time when he's not involved in soccer practice

The correct answer is b