(CNN) California voters registered with "no party preference" can choose among the Democratic, Libertarian, and American Independent parties to vote for a 2020 primary candidate, its secretary of state announced on Monday.

The Republican, Green, and Peace and Freedom, however, have opted to keep their primaries solely for voters registered with their respective parties.

The DNC's rules encourage state parties to open their primaries to unaffiliated voters, hoping to attract as large of a base as possible. In California -- where no party preference represents one of the largest voting blocs in the state -- those unaffiliated voters who choose to vote in the Democratic primary will have it recorded in their voter file, which will be available for the party to target in the future.

The parties are following the same arrangement they did during the June 2016 presidential primaries.

California holds a "jungle primary" for its congressional and state elections, a system that voters approved in a ballot initiative in 2010. Only the top two primary vote-getters make it onto the general election ballot, regardless of party.

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