How institutions, such as the government, may to maintain the privileges of some groups is a topic of interest for

The answer is: conflict theorists.

Explanation:

Conflict theorists are interested in power relationships between social groups and social classes. The conflict perspective has helped sociologists understand social change but also the maintanance of power and privileges by some groups. Therefore, how the government helps maintain the privileges of some grou is a topic of interest for sociologists using conflict perspective.

d. i assume the underlined word is "role." reformat if it isn't.

explanation:

role is closest to part because when replacing words, "playing a vital decision," "playing a vital activity," and "playing a vital dollar" don't make logical sense. the only meaningful choice is "playing a vital part."

this fits one of merriam-webster's definitions of role: "a function or part performed especially in a particular operation or process."