It's harder for alonso to recall the name of a colleague from work when he sees her in a grocery store than at her desk. this best illustrates

i am a priest who cares deeply about the church. i have been called here to explain my views on indulgences and other proposed reforms. i would like to explain why my views are consistent with the bible and are correct.

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."