In a centrally planned economy, the three key economic questions are answered by the a. marketplace alone b. marketplace with some government involvement c. central government with input from industry d. central government alone

answer: b has a great day

explanation:

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."