The correct answer is: caucus.

Explanation

A caucus is a meeting of a political party’s members where they discuss, debate, and then choose candidates or delegates to support a nominee. In U.S. presidential politics, caucuses involve in-person gatherings where participants often publicly realign and persuade others before a final count is made.

By contrast, a primary is a standard election using secret ballots, a convention is a larger party gathering (often national) to formally nominate candidates, and a general election is the final election in which voters choose among parties’ nominees for office.