Queen Mary of England put to death Protestants because they would not believe ideas about salvation.

the answer would be in this answer. someone already asked the question.  

i am confused, what is the question? i can you out if you put it into more depth.

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."