What characterizes an open primary?

An open primary is characterized by its flexibility in voter participation regarding political party affiliation. In an open primary system, voters have the freedom to choose which party primary they wish to vote in, regardless of their own registered party affiliation. This means that individuals who are registered with one political party can opt to participate in the primary election of another party, allowing for a broader range of participation and potentially encouraging more diverse voter engagement.

This system contrasts with closed primaries, where only voters who are registered with a specific party can vote in that party's primary. By allowing voters to cross party lines in an open primary, it can lead to a more dynamic electoral process, reflecting the preferences of a wider segment of the electorate. Thus, choice B accurately captures the defining feature of an open primary, highlighting its inclusive nature.