Lisa Addison introduces a bill on the floor of the Senate. She is most likely a constituent.
the governor
a senator
O the speaker

omg wow lol

explanation:

the answer your looking for is c. : )

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."