Which of the following is an example of a special interest group?
a. police unions
b. a parent group at a school
c. a student organization on campus
d. penn state university

The correct answer is - a student organisation on campus.

Explanation:

Interest groups form within a certain organisation, institution or a broader community (such as international interest groups) and share a specific interest. Many student organisations can be observed to form on campus, as students seek socializing and promoting what matters to them.

They gather around specific interests, such as language. For example, there can be a Chinese Language Student Society that supports learning of Chinese language. In particular,  by organizing meetings and workshops between native speaking students and those who are learning Chinese language.  

answer; i believe that the correct answer is ( rivers);