Which of the following best describe the Soviet satellite Sputnik?

O A. The first satellite launched into space?
O B. The first satellite to reach the moon?
O C. The first satellite to carry a person into space?
O D. The first satellite to carry a laboratory rat into space?

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."