In which primary can voters make choices from multiple parties simultaneously?

The correct response is that a blanket primary allows voters to choose candidates from multiple parties simultaneously. In a blanket primary, voters receive a single ballot that contains candidates from all parties, enabling them to select their preferred candidates across party lines for various offices. This format differs from closed and open primaries, where restrictions exist regarding party affiliation. Specifically, in a closed primary, only registered party members can vote for that party's candidates, while in an open primary, voters can choose which party primary to participate in but still only select candidates from one party. A run-off primary occurs when no candidate receives a majority of votes, necessitating a second round of voting between the top candidates, rather than allowing simultaneous selection from multiple parties.

Thus, the blanket primary's inclusive nature allows for a broader choice and reflects a more flexible electoral process, making it the right answer.