Why is a local government needed ? two reasons.

Local government serves a two-fold purpose. The first purpose is the administrative purpose of supplying goods and services; the other purpose is to represent and involve citizens in determining specific local public needs and how these local needs can be met. The significance of local government will be addressed

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."