5. A king gave his most important lords fiefs, which were a
grants of land.
b
large celebrations.
c
war horses.
d
market licenses.

i honestly have no idea

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."