Which of the following best explains the role of party convention delegates?(1 point) Responses They are pledged to a candidate but are allowed to change their vote at the convention. They are pledged to a candidate but are allowed to change their vote at the convention. They are pledged to a candidate and must vote for that person at the convention. They are pledged to a candidate and must vote for that person at the convention. They are only used by Republicans. They are only used by Republicans. They are only selected in closed primaries.