Based on the text, which statement best summarizes the reason many progressives supported the idea of holding primaries before general elections

The correct answer is The primary prevented party leaders from taking a role in choosing candidates

Before the primaries were introduced, the party leaders would select who would be the party candidate and people just had to vote for that candidate if they wanted to support their party, even if they disliked the candidate. Due to the primaries, it was made possible for people to choose their own candidate as long as they were members of the party.