Limiting he frequency of elections could have the following

a) people might have to go to the polls for primaries and general elections only.
b)officers would be elected annually.
c)more people might turn to the polls
d)terms of elected officials would be extended

answer; i believe that the correct answer is (d); // supercontinent

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."